Garry Kasparov, the former world chess champion turned opposition leader, said Thursday that the Kremlin had stopped him from running for president by preventing his supporters from meeting to nominate him.

Members of the Other Russia coalition, which Kasparov leads, say they had been unable to rent a Moscow auditorium, which they needed for a legally required vote to endorse the presidential bid.

Judging by the response organizers were getting from venue owners, authorities had been instructed to stop his group from meeting, Kasparov said.

Under the law, independent candidates can run for president only if an initiative group of at least 500 people meets formally to vote on his or her nomination. The deadline for informing the Central Elections Commission of such a meeting was Thursday.

Kasparov's spokeswoman, Marina Litvinovich, accused the government of pressuring the owners of Moscow auditoriums and meeting halls.

Kremlin spokesman Dmitry Peskov called the accusation absurd. "The Kremlin isn't involved in renting out halls, and blaming the Kremlin in any way in this case would be considered incorrect," he said.

Meanwhile, Kasparov's wife and daughter were detained at St. Petersburg's airport Wednesday as they tried to board an international flight, Kasparov's supporters said. They were released after having their documents checked and after the flight had departed.