A group of gay rights activists came under attack from neo-Nazi thugs when they tried to present a petition asking Moscow's mayor, Yuri Luzhkov, to lift a ban on a Gay Pride parade. He has previously dubbed gay rallies "satanic". Witnesses said riot police watched as far-right skinheads chanting "death to homosexuals" beat up several activists.

The police failed to arrest the skinheads but detained several of the Europeans - including the German MP Volker Beck, a member of the Green party, and the radical Italian MEP Marco Capatto. Riot police threw Mr Capatto into a police van. "Why don't you protect us?" he shouted.

"It was absolutely shocking," the gay rights campaigner Peter Tatchell told the Guardian yesterday. "The police stood there while people knocked me to the ground and kicked me. Four or five neo-Nazis attacked me. The police watched. At a certain point the police then arrested me and let my neo-Nazi attackers walk free."

Religious orthodox protesters and skinheads hurled eggs and stones - injuring Mr Tatchell in the eye. They also attacked Richard Fairbrass, the gay singer from the pop group Right Said Fred.

"When we were in the police van the police taunted us," Mr Tatchell said after his release. "They said, 'Are you a member of the sexual minority?' We said yes. They said, 'We are going to have some fun with you at the police station.' What happened here shows the flawed and failed nature of Russia's transition to democracy. There is no right to protest in Moscow."

The arrest of European parliamentarians is likely to further depress relations between the EU and Russia - which are at a lowpoint after an acrimonious summit this month in the Russian city of Samara. The chairwoman of Germany's Green party, Claudia Roth, yesterday called on the chancellor, Angela Merkel, to raise the issue of rights with President Vladimir Putin at next month's G8 summit.

As a member of the Council of Europe and signatory to the European convention on human rights, Russia is obliged to allow demonstrations. "It has been shown once again today that human rights are systematically abused in Putin's Russia," Ms Roth said.

The activists had tried to deliver a petition signed by 50 MEPs calling on Moscow's mayor to respect freedom of assembly, but 30 of them were arrested and they did not make it to his city hall office. Mr Beck was later released. Three Russian gay rights campaigners were kept in custody and charged with disobeying police.

Neo-Nazi thugs and an orthodox priest attacked the activists when they were freed several hours after their arrest, witnesses said. "This is terrible but I am not scared," a Russian named Alexey said, blood streaming from his face. "This is a pretty scary place, a pretty scary country if you are gay. But we won't give up until they allow us our rights."

Russia decriminalised homosexuality in 1993, but the gay community is still widely reviled. Last year Mr Luzhkov refused to allow a Gay Pride rally to take place.