A leading Russian opposition politician, former Deputy Prime Minister Boris Nemtsov Putin was shot and killed early Saturday in central Moscow.
Nemtsov’s murder comes just a day before an opposition rally was scheduled to take place in Moscow.
Boris Nemtsov, 55, was shot four times from a passing car as he was walking on a bridge with a female acquaintance, a Ukrainian citizen just outside the Kremlin.
Russian President Vladimir Putin, who quickly offered his condolences and called the murder a provocation, ordered Russia's top law enforcement chiefs to personally investigate Nemtsov's killing.
He served as a deputy prime minister in the 1990s, and once was seen as a possible successor to Boris Yeltsin, Russia's first elected president.
In condemning what he called Nemtsov's "brutal murder," President Obama urged the Russian government to conduct a "prompt, impartial and transparent investigation."
"Nemtsov was a tireless advocate for his country, seeking for his fellow Russian citizens the rights to which all people are entitled," Obama said in a statement. "I admired Nemtsov’s courageous dedication to the struggle against corruption in Russia and appreciated his willingness to share his candid views with me when we met in Moscow in 2009."