LVIV, Ukraine -- Ukrainian fighters in the tunnels underneath Mariupol's devastated steel plant held out against Russian troops Thursday in an increasingly desperate effort to deny Russia what would be its biggest success of the war yet: the complete capture of the strategic port city.
The battle came amid growing speculation that President Vladimir Putin wants to present the Russian people with a battlefield triumph -- or announce an escalation of the war -- in time for Victory Day on Monday. Victory Day is the biggest patriotic holiday on the Russian calendar, marking the Soviet Union's triumph over Nazi Germany.
Some 2,000 Ukrainian fighters, by Russia's most recent estimate, were holed up at Mariupol's Azovstal steelworks, the last pocket of resistance in a city largely reduced to rubble over the past two months. A few hundred civilians were also believed trapped there.
The defenders will "stand till the end. They only hope for a miracle," Kateryna Prokopenko said after speaking by phone with her husband, a leader of the steel plant defenders. "They won't surrender."
She said her husband, Azov Regiment commander Denys Prokopenko, told her he would love her forever.
"I am going mad from this. It seemed like words of goodbye," she said.
Ukrainian President Volodymyr Zelenskyy said the attack was preventing the evacuation of civilians remaining in the plant's underground bunkers.
"Just imagine this hell! And there are children there," he said late Thursday in his nightly video address. "More than two months of constant shelling, bombing, constant death."
The Russians managed to get inside with the help of an electrician who knew the layout, said Anton Gerashchenko, an adviser to Ukraine's Internal Affairs Ministry.
"He showed them the underground tunnels which are leading to the factory," Gerashchenko said in a video posted late Wednesday. "Yesterday, the Russians started storming these tunnels, using the information they received from the betrayer."
The Kremlin denied its troops were storming the plant.
The fall of Mariupol would deprive Ukraine of a vital port, allow Russia to establish a land corridor to the Crimean Peninsula, which it seized from Ukraine in 2014, and free up troops to fight elsewhere in the Donbas, the eastern industrial region that the Kremlin says is now its chief objective.
Capt. Sviatoslav Palamar, deputy commander of the Azov Regiment, pleaded on Ukrainian TV for the evacuation of civilians and wounded fighters from the steelworks, saying soldiers were "dying in agony due to the lack of proper treatment."
The Kremlin has demanded the troops surrender. They have refused. Russia has also accused them of preventing the civilians from leaving.
The head of the United Nations said another attempt to evacuate civilians from Mariupol and the plant was underway. U.N. Secretary-General Antonio Guterres said, "We must continue to do all we can to get people out of these hellscapes."
More than 100 civilians were rescued from the steelworks over the weekend. But many previous attempts to open safe corridors from Mariupol have fallen through, with Ukraine blaming shelling and firing by the Russians.
Meanwhile, 10 weeks into the devastating war, Ukraine's military claimed it recaptured some areas in the south and repelled other attacks in the east. Ukrainian and Russian forces are fighting village by village.
Pentagon spokesman John Kirby said Russian forces are making only "plodding" progress in the Donbas region.
The head of Britain's armed forces, Chief of the Defense Staff Adm. Tony Radakin, said Putin is "trying to rush to a tactical victory" before Victory Day. But he said Russian forces are struggling to gain momentum.
Radakin told British broadcaster Talk TV that Russia is using missiles and weapons at such a rate that it is in a "logistics war" to keep supplied. "This is going to be a hard slog," he said.
Fearful of new attacks surrounding Victory Day, the mayor of the western Ukrainian city of Ivano-Frankivsk urged residents to leave for the countryside over the long weekend and warned them not to gather in public places.
And the southeastern city of Zaporizhzhia, a key transit point for evacuees from Mariupol, announced a curfew from Sunday evening through Tuesday morning.
Russian Defense Ministry spokesman Maj. Gen. Igor Konashenkov said Russian bombardment Thursday hit dozens of Ukrainian military targets, including troop concentrations in the east, an artillery battery near the eastern settlement of Zarozhne, and rocket launchers near the southern city of Mykolaiv.
Five people were killed and dozens injured in shelling of cities in the Donbas over the past 24 hours, Ukrainian officials said, with shells hitting schools, apartments and a medical facility.
Ukrainian forces said they made some gains on the border of the southern regions of Kherson and Mykolaiv and repelled 11 Russian attacks in the Donetsk and Luhansk regions that make up the Donbas.
The Washington-based Institute for the Study of War said Ukrainian forces "have largely stalled Russian advances in eastern Ukraine," and intensified Russian airstrikes on transportation infrastructure in the western part of the country have failed to stop Western aid shipments to Ukraine.
But the war has devastated the country's medical infrastructure, Zelenskyy said in a video link to a charity event in the U.K., with nearly 400 health care facilities damaged or destroyed.
"There is simply a catastrophic situation regarding access to medical services and medicines" in areas occupied by Russian forces, he said. "Even the simplest drugs are lacking."
With the challenge of mine-clearing and rebuilding after the war in mind, Zelenskyy announced the launch of a global fundraising platform called United24.
At the same time, Poland hosted an international donor conference that raised $6.5 billion in humanitarian aid. The gathering was attended by prime ministers and ambassadors from many European countries, as well as representatives of nations farther afield and some businesses.
In addition, a Ukrainian Cabinet body began to develop proposals for a comprehensive postwar reconstruction plan, while Zelenskyy also urged Western allies to put forward a program similar to the post-World War II Marshall Plan plan to help Ukraine rebuild.
BELARUS, BULGARIA
In other developments, Belarus' authoritarian president, Alexander Lukashenko, defended Russia's invasion of Ukraine in an interview with The Associated Press but said he didn't expect the conflict to "drag on this way."
Lukashenko, whose country was used by the Russians as a launchpad for the invasion, said Moscow had to act because Kyiv was "provoking" Russia.
But he also created some distance between himself and the Kremlin, repeatedly calling for an end to the conflict and referring to it as a "war" -- a term Moscow refuses to use. It insists on calling the fighting a "special military operation."
And in anticipation of a European Union embargo on Russian crude oil, Bulgaria said Thursday that it's looking for an exemption because of its dependence on supplies from Russia. Slovakia and Hungary have already asked for such exemptions.
Bulgaria's only oil refinery, near the Black Sea port of Burgas, is owned by Russian oil giant Lukoil and is the main fuel supplier in the country.
Still, Deputy Prime Minister Assen Vassilev said the refinery is already processing up to 50% non-Russian crude and theoretically should be able to eliminate Russian oil.
"Bulgaria, technologically, can do without Russian crude oil, but this would significantly increase fuel prices," Vassilev said. "In case the European Commission weighs some exemptions, we would like to take advantage of it, because it will be in the best interest of Bulgarian consumers."
Russia stopped gas deliveries to Bulgaria last week in response to Sofia's refusal to pay in rubles, saying it violates contracts.
U.S. INTELLIGENCE HELP
During the war, the United States has provided intelligence about Russian units that has allowed Ukrainians to target and kill many of the Russian generals who have died in action in the Ukraine war, according to senior U.S. officials.
Ukrainian officials said they have killed approximately 12 generals on the front lines, a number that has astonished military analysts.
The targeting help is part of a classified effort by the Biden administration to provide real-time battlefield intelligence to Ukraine. That intelligence also includes anticipated Russian troop movements gleaned from recent U.S. assessments of Moscow's secret battle plan for the fighting in the Donbas region of eastern Ukraine, the officials said. Officials declined to specify how many generals had been killed as a result of U.S. assistance.
The United States has focused on providing the location and other details about the Russian military's mobile headquarters, which relocate frequently. Ukrainian officials have combined that geographic information with their own intelligence -- including intercepted communications that alert the Ukrainian military to the presence of senior Russian officers -- to conduct artillery strikes and other attacks that have killed Russian officers.
The U.S. says it also shared intelligence with Ukraine about the location of the Russian missile cruiser Moskva before the strike that sank the warship, an incident that was a high-profile failure for Russia's military.
An American official said Thursday that Ukraine alone decided to target and sink the flagship of Russia's Black Sea Fleet using its own anti-ship missiles. But given Russia's attacks on the Ukrainian coastline from the sea, the U.S. has provided "a range of intelligence" that includes locations of those ships, said the official.
The official who spoke Thursday said the U.S. was not aware that Ukraine planned to strike the Moskva until after it conducted the operation. NBC News first reported on the American role in the sinking of the ship.
The intelligence sharing is part of a stepped-up flow in U.S. assistance that includes heavier weapons and tens of billions of dollars in aid, demonstrating how quickly the early U.S. restraints on support for Ukraine have shifted as the war enters a new stage that could play out over months.
The administration has sought to keep much of the battlefield intelligence secret, out of fear it will be seen as an escalation and provoke Putin into a wider war. U.S. officials would not describe how they have acquired information on Russian troop headquarters, for fear of endangering their methods of collection. But throughout the war, the U.S. intelligence agencies have used a variety of sources, including classified and commercial satellites, to trace Russian troop movements.
Defense Secretary Lloyd Austin went so far as to say last month that "we want to see Russia weakened to the degree it cannot do the kinds of things that it has done in invading Ukraine."
Asked about the intelligence being provided to the Ukrainians, John Kirby, the Pentagon spokesperson, said that "we will not speak to the details of that information." But he acknowledged that the U.S. provides "Ukraine with information and intelligence that they can use to defend themselves."
Adrienne Watson, a National Security Council spokesperson, said in a statement that the battlefield intelligence was not provided to the Ukrainians "with the intent to kill Russian generals."
The United States routinely provides information about the movement of Russian troops and equipment, and helps Ukraine confirm the location of critical targets. Other NATO allies also give real-time intelligence to the Ukrainian military.
Although the administration remains wary of inflaming Putin to the point that he further escalates his attacks -- President Joe Biden has said he will not send U.S. troops to Ukraine or establish a no-fly zone there -- current and former officials said the White House finds some value in warning Russia that Ukraine has the weight of the United States and NATO behind it.
Some European officials believe, despite Putin's rhetoric that Russia is battling NATO and the West, he has so far been deterred from starting a wider war. U.S. officials are less certain and have been debating for weeks why Putin has not done more to escalate the conflict.
Officials said Moscow has its own calculations to weigh, including whether it can handle a bigger war, particularly one that would allow NATO to invoke its mutual defense charter or enter the war more directly.
"Clearly, we want the Russians to know on some level that we are helping the Ukrainians to this extent, and we will continue to do so," said Evelyn Farkas, the former top Defense Department official for Russia and Ukraine in the Obama administration and currently the executive director of the McCain Institute. "We will give them everything they need to win, and we're not afraid of Vladimir Putin's reaction to that. We won't be self-deterred."
Information for this article was contributed by Jon Gambrell, Cara Anna, Yesica Fisch, Inna Varenytsia, David Keyton, Yuras Karmanau, Mstyslav Chernov, Aamer Madhani, Nomaan Merchant, Lolita C. Baldor and staff members of The Associated Press and Julian E. Barnes, Helene Cooper and Eric Schmitt of The New York Times.
An Antonov An-124 cargo aircraft is seen in the hangar destroyed during recent fighting between Russian and Ukrainian forces, at the Antonov airport in Hostomel, on the outskirts of Kyiv, Ukraine, Thursday, May 5, 2022. (AP Photo/Efrem Lukatsky)
In this handout photo taken from video released on Wednesday, May 4, 2022 by Donetsk People's Republic Interior Ministry Press Service, Smoke rises from the Metallurgical Combine Azovstal in Mariupol, in territory under the government of the Donetsk People's Republic, eastern Ukraine. Heavy fighting is raging at the besieged steel plant in Mariupol as Russian forces attempt to finish off the city's last-ditch defenders and complete the capture of the strategically vital port. (Donetsk People's Republic Interior Ministry Press Service via AP)
Smoke rises from the Metallurgical Combine Azovstal in Mariupol, in territory under the government of the Donetsk People's Republic, eastern in Mariupol, Ukraine, Thursday, May 5, 2022. Heavy fighting is raging at the besieged steel plant in Mariupol as Russian forces attempt to finish off the city's last-ditch defenders and complete the capture of the strategically vital port. (AP Photo)
Teenagers on bicycles pass a bridge destroyed by shelling near Orihiv, Ukraine, Thursday, May 5, 2022. (AP Photo/Evgeniy Maloletka)
A Ukrainian sapper searches for unexploded explosives at the remains of the Antonov An-225, the world's biggest cargo aircraft destroyed during recent fighting between Russian and Ukrainian forces, at the Antonov airport in Hostomel, on the outskirts of Kyiv, Ukraine, Thursday, May 5, 2022. (AP Photo/Efrem Lukatsky)
Smoke rises from the Metallurgical Combine Azovstal in Mariupol, in territory under the government of the Donetsk People's Republic, eastern Ukraine, Wednesday, May 4, 2022. (AP Photo/Alexei Alexandrov)
Injured Natalia Rudneva, 59, reacts as her son was hospitalised after night shelling in Kramatorsk, Ukraine, Thursday, May 5, 2022.(AP Photo/Andriy Andriyenko)
In this handout photo taken from video released on Wednesday, May 4, 2022 by Donetsk People's Republic Interior Ministry Press Service, Smoke rises from the Metallurgical Combine Azovstal in Mariupol, in territory under the government of the Donetsk People's Republic, eastern Ukraine. Heavy fighting is raging at the besieged steel plant in Mariupol as Russian forces attempt to finish off the city's last-ditch defenders and complete the capture of the strategically vital port. (Donetsk People's Republic Interior Ministry Press Service via AP)
The gutted remains of the Antonov An-225, world's biggest cargo aircraft destroyed during recent fighting between Russian and Ukrainian forces, at the Antonov airport in Hostomel, on the outskirts of Kyiv, Ukraine, Thursday, May 5, 2022. (AP Photo/Efrem Lukatsky)