Clashes erupted when activists tried to break through police lines

Scuffles in Moscow

He and other opposition figures were detained during a rally organised by Mr Kasparov's Other Russia coalition.

Police moved in when protesters marched on the election commission. Mr Kasparov was charged with resisting arrest and organising an unauthorised protest.

The incident came a week before polls which supporters of President Vladimir Putin are widely expected to win.

Other Russia brings together a broad coalition of mainstream politicians, leftists and nationalists, all of whom are opposed to the Kremlin.

Movement growing

About 3,000 protesters attended Saturday's rally, carrying banners and calling for the country to be rid of President Putin.

Mr Kasparov is among the Kremlin's fiercest critics

The trouble broke out at the end of the rally when about 100 protesters tried to break through police lines.

They began to march to the election commission and were stopped by riot police.

The commission has barred Other Russia candidates from the 2 December election.

The authorities said they had authorised a rally, but not a march.

Attending the protest for the first time was Boris Nemtsov, the leader of one of the mainstream liberal parties, the Union of Right Forces - a sign that the movement is growing, says the BBC's Richard Galpin in Moscow.

Mr Putin stands down when Russia elects a new president in March 2008, as the constitution bars him from seeking a third consecutive term.

He has decided to stand as a parliamentary candidate - which effectively guarantees him a seat in the next parliament.

The Supreme Court has dismissed an opposition complaint against the move.