Russia's "Novaya gazeta" newspaper, where Politkovskaya worked, unveiled a commemorative plaque to the journalist. Commemorative gatherings and pickets were also organized at other locations in Moscow and in St. Petersburg.
In Berlin, a concert was staged to show solidarity with victims of violence and rights violations in Russia.
Politkovskaya, who reported on atrocities committed by Russian forces and pro-Kremlin armed groups in Chechnya, was shot dead outside her Moscow apartment on October 7, 2006. Five suspects are on trial for alleged involvement in her murder.
In a statement, Washington urged "redoubled efforts" to solve the case.
Several other Western governments and rights organizations issued similar statements.