MOSCOW -- Several thousand people have begun a march in Moscow in memory of Russian opposition leader Boris to mark the first anniversary of his killing.

Nemtsov was shot to death late at night as he and a companion walked across a bridge overlooking the Kremlin. The brutality so close to the centre of Russian power both frightened and angered supporters of the beleaguered opposition.

Nemtsov, who had been a prime minister during Boris Yeltsin's presidency, was a charismatic figure and a vehement critic of President Vladimir Putin.

"He was the embodiment of freedom and courage, he was a model for me," said marcher Kamala Igamberdiyeva, a 26-year-old accountant. "We still have a chance if the opposition shows wisdom and unites."

In Putin's decade-and-a-half in power, opposition groups have come under severe pressure, criticized by officials and state-controlled media as pawns of the West. Permission for rallies is frequently denied.

Many opposition supporters say that even if Putin had no direct hand in Nemtsov's killing, he bears responsibility for encouraging a truculent authoritarianism.

"Nemtsov's death was the result of the atmosphere of hatred in our country," said 78-year-old demonstrator Pavel Movshovich.

Five suspects have been arrested in the killing, all of them Chechens. The suspected triggerman served as an officer in the security forces of the Moscow-backed Chechen leader, Ramzan Kadyrov.

City authorities denied march organizers permission to hold a procession to the bridge, but gave permission for another route in central Moscow on Saturday.

On Saturday morning, U.S. Ambassador John Tefft laid a wreath at the bridge, saying he came to express hope that "some of the dreams that Boris Nemtsov had will come true in Russia."

In Ottawa, Foreign Affairs Minister Stephane Dion said Canada remembers Nemtsov's sacrifice and unwavering commitment to building a better future for Russians.

"On this sombre anniversary, we call on the Russian authorities to uphold the rights and freedoms for which Boris Nemtsov fought, strongly condemn all threats to Russian opposition leaders and activists, and bring to justice those who perpetrate acts of violence against such figures, including in the case of Boris Nemtsov," Dion said in a statement.

"Canada stands with its international partners in resolute support for human rights and accountable governance around the globe. Boris Nemtsov's life may have been tragically cut short one year ago, but his convictions and courage will continue to inspire us for years to come."