Russian Opposition Leader Killed In 'Politically Motivated' Attack A Day Before Major Anti-Putin Protest

Boris Nemtsov, a charismatic former deputy prime minister turned Russian opposition leader, was shot and killed in Moscow Saturday, officials said.

Nemtsov's death comes just a day before a planned protest against President Vladimir Putin's rule. The Kremlin said that Putin will personally oversee the investigation.

Nemtsov, who was 55, was a sharp critic of 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.

The Russian Interior Ministry, which oversees Russia's police force, said that Nemtsov was shot four times from a passing car as he was walking a bridge just outside the Kremlin shortly after midnight.

Interior Ministry spokeswoman Yelena Alexeyeva told reporters on the scene that Nemtsov was walking with a female acquaintance, a Ukrainian citizen, when a vehicle drove up and unidentified assailants shot him dead. The woman wasn't hurt.

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.

Ukraine and the West have accused Russia of backing the rebels there with troops and weapons. Moscow has denied the accusations, but large numbers of sophisticated heavy weapons in the rebels' possession has strained the credibility of its denials.

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.

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 served a deputy prime minister in the 1990s and once was seen as a possible successor to Boris Yeltsin, Russia's first elected president. After Putin was first elected in 2000, Nemtsov became one of the most vocal critics of his rule. He helped organize street protests and has relentlessly exposed official corruption.

He was one of the organizers of the Spring March opposition protest set for Sunday, which comes amid a severe economic downturn in Russia caused by low oil prices and Western sanctions.