Russia has seen a second weekend of protests, although turnout was significantly lower than one week ago. President Medvedev has dismissed US criticism as "Cold War talk."
About 1,500 protesters took to the streets in Moscow and other Russian cities on Saturday to demonstrate against the disputed December 4 parliamentary election.
The turnout of the protests was far below that of the rallies one week ago, when more than 50,000 demonstrated in Moscow, St. Petersburg and elsewhere.
Saturday's protests in Moscow had been organized by the center-left Yabloko party, which failed to win any seats in the upcoming parliament, receiving only 3.3 percent in the vote.
Prime Minister Vladimir Putin's United Russia party won an absolute majority in the Duma but lost the two-thirds majority it held in the previous term.
Critics say the party actually did far worse and only maintained the slimmest of majorities through ballot stuffing.
"We need a new election law and new, honest elections," Yabloko leader Grigory Yavlinsky told the crowd.
"Our goal is to change today's political system, which lies, which is corrupt and serves the interests of a small group of people," he said.
Nemtsov temporarily arrested
He said the police treated him "like an extremist leader."
"Only after they determined that the demonstration was authorized was I let free - the question is for how long," Nemtsov said.
Russian President Dmitry Medvedev meanwhile dismissed US allegations that the election was rigged.
"I was forced to tell President Barack Obama on the phone that the assessment of our election by the US is of no significance to us," Medvedev said on Saturday.
He said "commentary like that from the Cold War" as unacceptable.
Communists nominate Zyuganov
Also on Saturday, a Communist Party congress in Moscow nominated party leader Gennady Zyuganov as the party's candidate in next year's presidential vote.
In the disputed December 4 parliamentary elections, the Communist party got 19,2 percent, making it the second largest political force after United Russia.
In the 2012 presidential vote, Zyuganov is to run against Putin, who is widely expected to win the elections. Putin already served as president between 2000 and 2008 when term limits barred him from running again. He has been prime minister since then.
Author: Andreas Illmer (dpa, AFP, AP)
Editor: Holly Fox
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