A Tajik citizen was killed and a teenage boy was stabbed late last week in separate Moscow attacks that bore the hallmarks of hate crimes.

Five teenagers started a quarrel with two Tajik citizens walking at around 10 p.m. Thursday on Ulitsa Pokrovka in central Moscow, Interfax reported, citing police.

The teens stabbed one of the men repeatedly, and he died on the spot near 17 Ulitsa Pokrovka, the report said. His friend escaped with minor injuries.

No suspects have been detained in the attack.

The stabbing happened just a few hours after clashes between skinheads and anti-extremism campaigners in central Moscow.

Around 50 anti-extremism activists turned up at around 7 p.m. on Tverskaya Ulitsa to guard a gay rights flash mob, said Sova Center, an organization that monitors hate crimes. A group of skinheads also showed up for the flash mob, and they began to fight with the anti-extemism activists as the two groups followed the flash mob down the street, Sova Center said in a statement on its web site. One teenage boy was stabbed, it said.

An eyewitness said she saw young men and women attacking a teenage boy near 15 Tverskaya Ulitsa at around 7 p.m. "There were about 20 people attacking him," said Marina Kamenev, a reporter for The Moscow Times. They ran off ... and then one girl returned and spat on him."

It was unclear whether he was the same boy mentioned by Sova Center.

The victim had short hair, but so did a number of the attackers, Kamenev said.

She said police officers did not intervene.

Also Thursday evening, 70 to 80 people brawled near a popular gay cruising area at the Kitai Gorod metro station, Sova said. Anti-extremism activists used pepper spray during the clashes, it said.