A leading gay rights activist was detained at a Moscow airport and resurfaced in Minsk in a bizarre case that his supporters linked to his campaign to pressure Moscow's City Hall to allow gay pride rallies.

Nikolai Alexeyev was held by police shortly before the departure of his flight to Geneva from Moscow's Domodedovo Airport on Wednesday evening, gay activist Nikolai Bayev told The Moscow Times.

"He was sitting in the airport's waiting hall when he was approached by border guards and customs and police officers," Bayev said, citing a text message from Alexeyev.

Alexeyev also sent out text messages saying he was being taken 600 kilometers from Moscow in an unspecified direction, Solidarity opposition activist Alexei Davydov told Ekho Moskvy radio.

Alexeyev said in his messages that unspecified officials were pressuring him to cancel an upcoming rally against Mayor Yury Luzhkov and to call off lawsuits filed in the European Court of Human Rights over gay pride rallies banned by City Hall, Bayev said.

Later Thursday, Alexeyev informed his friends in another text message that he was in Minsk and pledged to return to Moscow, Davydov said, Interfax reported. It was unclear how he had arrived in Belarus.

Alexeyev continued to send out text messages during the day, but his cell phone was switched off when The Moscow Times tried to reach him Thursday afternoon.

An airport spokeswoman, Yelena Galanova, said Alexeyev had refused to obey security measures.

“He refused to remove his shoes during a check. The airport security service informed his air carrier about it, and the company removed him from the flight,” Galanova told RIA-Novosti.

She did not elaborate and could not be reached for comment Thursday afternoon.

The Marriage Equality U.S.A. gay rights organization and German lawmaker Volker Beck, who has participated in several banned gay rallies in Moscow, said they requested an explanation from Russian authorities over Alexeyev's detention.

Alexeyev and his supporters plan to picket Luzhkov's office on the mayor's 74th birthday on Tuesday with posters accusing him of being homophobic. Luzhkov has denounced gay rallies as “satanic” and called gay activists “homos” last year. A Moscow court later ruled that the word was not offensive.

In a separate indication of the authorities' disapproval of gay activism, a sanctioned gay festival in St. Petersburg had to relocate ahead of its opening Thursday after its host denied space for the event on the insistence of the city's cultural committee, organizers said.

The festival was scheduled to run until Oct. 2 at the exhibition center of the Union of Artists in St. Petersburg but had to move out, organizers said. It promptly found another venue, the Vegan club, and managed to open Thursday afternoon.

Local parents had asked the city authorities to ban the festival, which consists of exhibitions, discussions, music concerts and poetry recitals, because it would "ruin the souls of children and teenagers."