MOSCOW -- President Vladimir Putin on Wednesday called the slaying of his top critic a "disgrace" to Russia, while the opposition promised to complete Boris Nemtsov's work on a report documenting evidence of Russian troops' involvement in fighting in eastern Ukraine.
Putin condemned the slaying of Nemtsov, who was gunned down while walking on a bridge near the Kremlin late Friday.
The Russian leader had sent his condolences to Nemtsov's mother, but his comments Wednesday were his first public remarks on the slaying.
"The most serious attention must be paid to high-profile crimes, including those with a political motive," Putin said in televised remarks to top officials of the Interior Ministry. "We must finally rid Russia of the disgrace and tragedy of the kinds of things we recently saw and experienced: I mean the audacious murder of Boris Nemtsov in the very center of the capital."
Nemtsov, 55, one of Putin's most vehement critics, was killed just hours after a radio interview in which he denounced the president for his "mad, aggressive" policies in Ukraine. Before his death, he was working on a report about Russian involvement in the war in eastern Ukraine.
Opposition activist Ilya Yashin said police had seized computers and documents during searches in Nemtsov's apartment in Moscow and his office in Yaroslavl, where he worked as a regional lawmaker.
But Yashin said he and others have found some fragments related to Nemtsov's work and hope to publish a report.
"He has kept his materials in different places, including with his associates and friends, and we have managed to get access to some of them," Yashin said. "We will try to restore bits and pieces of the work that Boris has started but failed to complete, and we will do everything to bring this work to the end, so that the report will see the light. It's very important for us."
No suspects have been detained yet in Nemtsov's killing, despite an offer of nearly $50,000 for information related to the case.
Putin dubbed Nemtsov's killing a "provocation," and TV networks quickly followed up, blaming Western intelligence agencies, Ukrainian agents or even the opposition.
The nation's top investigative agency echoed Putin's comments, saying it was looking into whether Nemtsov had been a "sacrificial victim" to destabilize Russia. It said it was also investigating whether Islamic extremism, the Ukraine conflict and Nemtsov's personal life were factors.
Kremlin-controlled media focused on a 23-year-old Ukrainian model who was with Nemtsov when he was slain.
The woman, Anna Duritskaya, told Russian Dozhd television that Nemtsov was shot from behind and that she hadn't seen the attacker, nor could she identify the license plate nor make of the gunman's getaway car.
Also on Wednesday, a Moscow court refused to release a Ukrainian military officer who has been on hunger strike in a Russian prison since mid-December and has become a national hero in Ukraine.
The case of Nadezhda Savchenko, 33, has attracted attention as concerns rise about her health. The United States and the European Union have urged Russia to release the woman who is seen as a symbol of resistance in Ukraine and has been elected to parliament.
Savchenko has been in Russian custody since June on charges that she provided guidance for a mortar attack that killed two Russian journalists who were covering the war.
The circumstances of her capture remain unclear. Russia's Investigative Committee alleges Savchenko crossed into Russia voluntarily and illegally, disguised as a refugee. But Savchenko says she was captured by the separatists in eastern Ukraine and taken across the border into Russia.
The fighting in eastern Ukraine, which began in April after Russia annexed the mostly Russian-speaking Crimean Peninsula, has killed more than 6,000 people and forced more than 1 million to flee their homes.
Ukraine and the West have accused Moscow of backing the pro-Russia rebellion in eastern Ukraine with troops and weapons -- accusations the Kremlin has denied even though NATO said it has satellite pictures proving Russia's involvement.
In the United States, members of the House Foreign Affairs Committee on Wednesday stepped up pressure on President Barack Obama's administration to support Ukraine with weapons to defend against attacks from the pro-Russia rebels.
"To not decide is to decide," said Chairman Ed Royce, R-Calif.
Victoria Nuland, assistant secretary of state for European and Eurasian affairs, told the committee that the U.S. is watching whether agreements that led to last month's cease-fire are implemented.
Lawmakers from both parties have urged Obama to provide Ukraine with weapons. Many European governments, however, oppose any U.S. move to provide military support for Ukraine's government, fearing that might spark a wider proxy war.
Nuland said Obama has received recommendations and advice from Cabinet agencies but has not yet made a decision. Nuland declined to say whether the State Department has advised the White House to send arms to Ukraine.
Information for this article was contributed by Jim Heintz, Raf Casert, Peter Leonard, and Deb Riechmann of The Associated Press.
A Section on 03/05/2015