Kasparov questioned by Russian state security agency

Investigators from Russia's security agency today questioned opposition leader Garry Kasparov, days after massive police crackdowns on anti-government protests in Moscow and St Petersburg last weekend.

Kasparov was summoned by the Federal Security Service, or FSB, the main successor of the Soviet KGB, to discuss recent statements that the agency believes may constitute illegal calls for extremist activity, his aide Marina Litvinovich said.

Kasparov, a former word chess champion who has become a vocal critic of President Vladimir Putin and is seeking to unite opposition forces before crucial elections over the next year, entered an FSB building near the agency's headquarters at Lubyanka square in central Moscow in the morning.

He was to meet with two investigators for separate discussions, Litvinovich said - one about statements he made to a radio station earlier this month, the other about items in a newspaper published by his opposition group, the United Civil Front, urging people to attend the weekend demonstrations.

She said it was not clear whether the authorities would open a criminal case against Kasparov on charges of inciting extremism - a move that would raise the stakes in the Kremlin's confrontation with opponents - and contended that the FSB's suspicions were groundless.

"The FSB is equating dissatisfaction with the current Russian leadership with extremism," she said. "If you shout a slogan against Putin, you are labelled an extremist."

Kasparov was detained Saturday while trying to lead a small group of protesters through lines of police ringing the Moscow square where opposition forces planned to hold an unauthorised demonstration and march. He was released hours later and fined for participating in the rally - one of a series of "Dissenters' Marches" organised by his group and others.

Officers clashed with about 200 demonstrators outside the police precinct where Kasparov was being held, beating them with night-sticks and fists.

Police also beat dozens of people after an authorised demonstration in St. Petersburg on Sunday, and hundreds of people - including demonstrators and bystanders - were detained in the two cities.

The crackdown has drawn widespread criticism from human rights groups and reinforced opposition contentions that the government is strangling democracy and suppressing dissent before December parliamentary elections and a presidential vote next March.

Putin is constitutionally barred from running for a third straight term, and analysts say those surrounding him want to ensure they remain in power.

In December, authorities raided the United Civil Front's office, taking copies of documents in a search they said was connected to suspicions it was involved in extremist activity, according to Litvinovich. Kasparov said at the time that the search was an example of Russian authorities using laws on extremism to crack down on dissent.

Yesterday, a Moscow court granted the chief prosecutor's request to classify the National Bolshevik Party as an extremist organisation, whose supporters also participated in the recent protests. The ruling will allow for tougher punishment for alleged members and could discourage other Kremlin opponents from joining them in protests.