Gary Kasparov Hit with Chessboard.

Garry Kasparov, the world's former No. 1 chess player who quit the professional game last month to focus on politics, said Saturday he had been hit over the head with a chessboard in a politically motivated attack.

Kasparov, an outspoken critic of President Vladimir Putin, was not injured Friday when he was hit with the chessboard after signing it for a young man at an event in Moscow.

A spokeswoman for Kasparov, Marina Litvinovich, said the assailant told the chess champion: "I admired you as a chess player, but you gave that up for politics."

She said the unidentified attacker - who did not reveal his political allegiance - tried to hit Kasparov again but was hauled away by security guards.

"It was a fairly nasty incident, it was not very pleasant psychologically," Kasparov told the private NTV television.

The 41-year-old Kasparov, a brilliant and aggressive tactician regarded by many as the greatest chess player of all time, has been ranked No. 1 in the world since 1984.

He retired last month, saying he planned to focus on politics and do "everything in my power to resist Putin's dictatorship." He plays a leading role in the Committee 2008: Free Choice, a group formed by liberal opposition leaders.

Putin has been accused of stifling democratic freedoms by placing national television under effective state control and centralizing power by boosting Kremlin control of parliament and country's regions.