Boris Nemtsov shot dead: President Obama condemns brutal murder of Putin opponent

Obama said Nemtsov was a 'tireless advocate' for Russia and for the rights of Russian citizens

Nemsov has been an outspoken critic of Putin (AFP/Getty Images)

President Barack Obama has condemned the killing of prominent Russian opposition figure Boris Nemtsov.

Obama said in a statement that Nemtsov was brutally murdered and called on Russia's government to perform a "prompt, impartial and transparent" investigation to bring the perpetrators to justice.

Nemtsov is a former deputy prime minister who later became a prominent opposition leader and a sharp critic of Russian President Vladimir Putin. The 55-year-old was shot and killed in Moscow close to the Kremlin.

Obama said Nemtsov was a "tireless advocate" for Russia and for the rights of Russian citizens and praised the politician for fighting corruption. Obama and Nemtsov met in Moscow in 2009.