Boris Nemtsov, Russian opposition leader, shot dead in central Moscow

Russian opposition leader Boris Nemtsov has been shot dead in central Moscow, in what president Vladimir Putin says looks like a "contract killing".

Mr Nemtsov, 55, was shot at multipletimes as he walked along the Bolshoi Moskvoretsky bridge, not far from the Kremlin.

The attacker, who has not been identified, was in a white car that sped off after the attack.

Officials said Mr Nemtsov had been walking on the bridge over the Moskva River with a Ukrainian woman.

Mr Nemtsov was shot "from a car as he was walking along the Bolshoi Moskvoretsky bridge", investigators said, adding that it had opened a criminal probe.

Mr Nemtsov had been due to take part in the first big opposition protest in months in the Russian capital on Sunday.

"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.

Mikhail Kasyanov, a fellow opposition leader, said organisers had scrapped plans to hold the opposition rally and planned to conduct a funeral march in central Moscow instead.

"Nemtsov B.E. died at 23:40 hours as a result of four shots in the back," an interior ministry spokeswoman said.

Mr Putin's spokesman, Dmitry Peskov, said the president believed the shooting had the hallmarks of a "contract killing" and could also be a "provocation" ahead of the rally.

He said Mr Putin had been quickly informed of the killing and the president had expressed his condolences and ordered the security agencies to investigate.

He said the Russian leader had taken the investigation "under personal control".

Mr Nemtsov had been quoted as saying he was concerned that the president might want him dead over his opposition to the conflict in Ukraine.

Police cars sealed off the bridge close to the red walls of the Kremlin and Red Square after the attack.

Mr Kasyanov told reporters at the bridge: "That a leader of the opposition could be shot beside the walls of the Kremlin is beyond imagination. There can be only one version: that he was shot for telling the truth."

Mr Kasyanov said it was payback "for the fact that Boris consistently, for many, many years fought for Russia to be a free democratic country."

A fighter for rights and democracy

Mr Nemtsov launched his political career 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 led several opposition parties and groups.

Interior ministry spokeswoman Yelena Alekseyeva told reporters at the scene that Mr Nemtsov was walking with a woman from Ukraine when he was shot.

She said the woman was being questioned.

Sunday's opposition march was intended as a protest against the war in east Ukraine, where pro-Russian rebels have seized a swathe of territory.

Interior ministry spokeswoman Yelena Alekseyeva said Mr Nemtsov was hit by four bullets.

Opposition figure Ksenia Sobchak said Mr Nemtsov had been preparing a report on the presence of Russian troops in Ukraine.

The Kremlin strongly denies allegations by Kiev and Western capitals that it has sent troops and advanced weaponry to back the rebels.

Like other opposition leaders, Mr Nemtsov was a fighter against corruption.

In other reports, he condemned massive overspending on the Sochi Winter Olympics by the Russian authorities and listed the many state buildings, helicopters and planes that Mr Putin has at his disposal.

Mr Nemtsov was also one of the leaders of mass rallies in the winter of 2011-12 that became the biggest protests against Mr Putin since the former KGB spy rose to power in 2000.

Alexei Venediktov, editor-in-chief of Echo of Moscow radio, wrote that Mr Nemtsov, who leaves behind four children and an elderly mother, had known he had taken risks by openly criticising Mr Putin.

"But I will not leave Russia, who would fight then?" he quoted the veteran politician as saying.

US president Barack Obama condemned the "vicious murder" of Mr Nemtsov, whom he had met on a visit to Moscow, and called on the Russian government to conduct a prompt and impartial investigation of the killing.

"We call upon the Russian government to conduct a prompt, impartial, and transparent investigation into the circumstances of his murder and ensure that those responsible for this vicious killing are brought to justice," Mr Obama said in a statement.

"Nemtsov was a tireless advocate for his country, seeking for his fellow Russian citizens the rights to which all people are entitled.

"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," Mr Obama added, calling Mr Nemtsov a "dedicated" and "eloquent defender" of rights.

• AFP/Reuters*