The demonstration began peacefully with dozens of journalists and scores of uniformed officers and Omon riot police congregating near a statue opposite Mayor Luzhkov's offices on Tverskaya Street, one of Moscow's busiest thoroughfares.
Orthodox extremists and nationalists arrived to speak to journalists and denounce the event.
Mr Alexeyev was attempting to deliver a petition signed by more than 50 MEPs urging Mr Luzhkov to allow such events.
A
gay rights activist was punched in the face by an anti-gay rights protester.
After receiving the blow, he leaned on a lamppost and shouted: "Someone protect me, Someone protect me," before being roughly escorted away by riot police.
His attacker was not detained.
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