DONETSK, Ukraine -- Pro-Russia rebels in eastern Ukraine rejected a previously signed peace deal Friday and launched a new multi-pronged offensive against Ukrainian government troops, upending recent European attempts to mediate an end to the fighting.
The main separatist leader in the rebellious Donetsk region vowed to push Ukrainian soldiers out of the area and said insurgents would not take part in any more cease-fire talks. Another rebel went even further, saying they would not abide by a previously signed peace deal.
Separatist leader Alexander Zakharchenko said rebel fighters went on the offensive to gain more territory and forestall a Ukrainian attack. He declared they would push government troops to the border of the Donetsk region and possibly beyond.
"Attempts to talk about a cease-fire will no longer be undertaken by our side," Zakharchenko said.
The peace deal signed in September in the Belarusian capital of Minsk envisaged a cease-fire and a pullout of heavy weapons from a division line in eastern Ukraine. It has been repeatedly violated by both sides, and heavy artillery and rocket barrages have increased the civilian death toll in the past few weeks.
Foreign ministers from Russia, Ukraine, France and Germany agreed Wednesday to revive that division line, but fighting has continued unabated.
The United Nations human-rights agency on Friday raised its estimate of the conflict's overall death toll to nearly 5,100 since April. About 262 people were killed in the conflict from Jan. 13 to Wednesday, an average of 29 a day, "the most deadly period" since the truce was signed, the U.N. said.
The world body bases its estimate on official morgue and hospital reports, and analysts think it understates the total death toll.
The tentative peace deal forged this week in Berlin called for Ukrainian troops and pro-Russia separatists to pull back their heavy arms 9 miles on either side of the line, although there was no agreement on a withdrawal of troops.
But rebel spokesman Eduard Basurin threw that agreement into doubt, saying the insurgents "will no longer consider the Minsk agreement in the form it was signed," although he said they remained open for peace talks.
Basurin's statement contradicted the official position of Russia, which has repeatedly pledged respect for the Minsk agreement, even though it has been reluctant to meet its end of the deal: the withdrawal of foreign fighters and the monitoring of the Russian-Ukrainian border by the Organization for Security and Cooperation in Europe.
Western nations think Russia is supplying fighters and weapons to the rebels in eastern Ukraine, an accusation Moscow has denied.
Battles intensified last weekend over Donetsk airport, which has been reduced to rubble by months of clashes. Rebels eventually took control of its terminal. Fighting has continued on its fringes.
Zakharchenko said rebel fighters were advancing in three directions in the Donetsk region and also pressing their attack in two other areas in the Luhansk region.
"We will hit them until we reach the border of Donetsk region, and ... if I see the danger for Donetsk from any other city, I will destroy this threat there," he said.
Zakharchenko has threatened to expand his territory before, but this time, a top NATO official confirmed that rebels had pushed west and received reinforcements.
U.S. Air Force Gen. Philip Breedlove said air-defense and electronic-warfare equipment were detected in eastern Ukraine -- hardware that, in the past, coincided with the incursion of Russian troops into Ukraine, he said.
While the rebel leader spoke of his own side's offensive, Russian officials claimed that the Ukrainian government was responsible for the recent increase in fighting in the east.
President Vladimir Putin said in comments to state officials that "the Kiev authorities have given an official order to start large-scale military operations practically throughout the whole line of contact," Reuters reported.
He said Ukrainian troops were shelling densely populated areas indiscriminately, causing dozens of civilian casualties, according to a Kremlin transcript.
The government in Kiev rejected the allegation.
"Ukrainian servicemen, unlike the militants, do not fire at residential blocks," military spokesman Andriy Lysenko said.
Ukrainian President Petro Poroshenko has said stern retribution would await anybody violating the peace agreements. After a speech Wednesday at an international economic forum in Davos, Switzerland, he rushed home to deal with the escalating fighting.
"If the enemy doesn't want to abide by the cease-fire, if he doesn't want to put an end to the suffering of peaceful people, Ukrainian villages and towns, we will smash them in the teeth," Poroshenko told top defense officials.
In Washington, U.S. State Department spokesman Jen Psaki voiced concern about the increasing bloodshed Friday.
"Ukraine has implemented cease-fire after cease-fire, but the Russia-backed separatists have responded with violence," she said, citing 1,000 attacks since early December and the deaths of 262 people in the last nine days.
Russia, she added, "holds the keys to peacefully resolving a conflict it started and bears a responsibility to end the violence."
The pro-Russia insurgency flared up in April in the Donetsk and Luhansk regions in eastern Ukraine after Russia's annexation of Ukraine's Crimean peninsula. Russia insists that it does not support the rebels, but Western military officials say the sheer number of heavy weapons under rebel control belies that claim.
At Davos, a Russian deputy prime minister vowed that Moscow would not be cowed by the sanctions the West has imposed upon Russia for its actions in Ukraine.
Igor Shuvalov warned the West against trying to topple Putin, reflecting the Kremlin's view that sanctions from the European Union and U.S. are aimed at regime change.
"When a Russian feels any foreign pressure, he will never give up his leader," Shuvalov said Friday. "Never. We will survive any hardship in the country -- eat less food, use less electricity."
The Russian currency has lost half its value in recent months from the double blow of sanctions and a plunge in world oil prices.
Information for this article was contributed by Mstyslav Chernov, Matthew Lee, Vladimir Isachenkov, Carlo Poivano and Nataliya Vasilyeva of The Associated Press; by Andrew E. Kramer of The New York Times; and by Mark Raczkiewycz, Daryna Krasnolutska, Stefan Riecher, Olga Tanas, Alexei Anishchuk, Patrick Donahue, Tony Czuczka and Rainer Buergin of Bloomberg News.
A Section on 01/24/2015