Russian opposition politician Boris Nemtsov was shot dead in Moscow on Friday, government officials have confirmed.
The former deputy prime minister was killed by an unidentified attacker close to the Kremlin, according to reports. He was shot numerous times, the Russian government told Interfax news agency in a statement.
Nemtsov, 55, was a sharp critic of President Vladimir Putin, assailing the government's inefficiency, rampant corruption and the Kremlin's policy on Ukraine, which has strained Russia-West ties to a degree unseen since Cold War times. His death comes just a day before a planned protest against Putin's rule.
Ukrainian President Petro Poroshenko said on Saturday that he believes Nemtsov was murdered because he planned to disclose evidence of Russia's involvement in Ukraine's separatist conflict. "He (Nemtsov) said he would reveal persuasive evidence of the involvement of Russian armed forces in Ukraine," Poroshenko said in televised comments on Saturday. "Someone was very afraid of this."
Opposition activist Ilya Yashin said on Ekho Moskvy radio that he last spoke with Nemtsov two days before the killing. Nemtsov was working on a report presenting evidence that he believed proved Russia's direct involvement in the separatist rebellion that erupted in eastern Ukraine last year.
Yashin said he had no doubt that Nemtsov's murder was politically motivated.
"Boris Nemtsov was a stark opposition leader who criticized the most important state officials in our country, including President Vladimir Putin. As we have seen, such criticism in Russia is dangerous for one's life," he said.
Russia's Investigative Committee confirmed the death, saying it had opened a criminal probe.
"According to preliminary information, an unidentified person shot at Boris Nemtsov no fewer than seven to eight times from a car as he was walking along the Bolshoi Moskvoretsky bridge," investigators said in a statement.
The committee, which reports directly to Putin, said that "experienced" investigators had been put on the case. Putin condemned the murder, suggesting that it may have been a contract killing.
Putin's spokesman, Dmitry Peskov, told Russian media that the shooting could also be a "provocation" ahead of a big protest planned in Moscow over the weekend.
He added that Putin had been quickly informed of the killing and that the president had expressed his condolences and ordered the security agencies to investigate. Meanwhile, in the telegram to Dina Eydman, Nemtsov's mother, Putin said, "Everything will be done so that the organizers and executors of this vile and cynical murder are punished."
Political analyst Stanislav Belkovsky told Ekho Mosvky radio station that he did not believe that Nemtsov's death would in any way serve Putin's interests.
"But the atmosphere of hatred toward alternative thinkers that has formed over the past year, since the annexation of Crimea, may have played its role," Belkovsky said, referring to the surge of intense and officially endorsed nationalist discourse increasingly prevalent in Russia since it annexed Ukraine's Crimean Peninsula.
Nemtsov launched his political career in 1991 as the governor of Nizhny Novgorod region in central Russia and became a vice prime minister in the late 1990s under the presidency of Boris Yeltsin.
After leaving parliament in 2003, he helped establish and lead several opposition parties and groups. Nemtsov's murder comes ahead of a major opposition rally scheduled to take place on March 1.
With wire services