A teenager has been stabbed to death in an attack possibly organized by Spartak Moscow football fans on the Internet.

The 16-year-old boy died in a "mass brawl" near the Kitai-Gorod metro station on Sunday evening, a spokesman for the Investigative Committee said Monday.

"A murder case has been opened, but no further details can be given as the case is ongoing," said the spokesman, speaking on customary condition of anonymity.

The spokesman refused to identify the teenager.

News reports identified the victim as Alexei Krylov and said he and the attackers belonged to rival skinhead groups.

Novaya Gazeta, citing an unidentified law enforcement official, reported that 15 skinheads who support xenophobic violence attacked Krylov and several of his friends, who belong to SHARP, or Skinheads Against Racial Prejudice.

Krylov, who died of multiple stab wounds at the scene, had attended a punk concert with his friends at the nearby Art Garbage club. He lived in the town of Noginsk near Moscow, the newspaper said.

Visitors to the http://fanat1k.ru web site, run by Spartak fans who support xenophobic violence, apparently planned the attack late last week.

While the entries on the web site's forums had been deleted Monday, versions of the pages cached by web pages remained viewable.

"A couple of words of advice to those planning to hang around Kitai-Gorod on Sunday," began one entry, posted by the user Perovsky, who is listed on the web site as an administrator.

"Why don't a couple of us go down there and check out the vicinity of the club. Dress like a regular person ... but don't go too close," the posting said. "On Sunday this thread will be deleted."

Another user asked whether there would be metal detectors at the club's entrance.

"If there are, then the SHARPs will get it outside. If not, then we will go in ourselves," said a third user, who called himself Slavka 'Oi!

Web site administrators did not reply to an e-mailed request for comment.

In unrelated Spartak violence, around 200 fans were detained after the club's Russian Premier League opener against Zenit St. Petersburg last weekend.

Police said the fans were held for petty crimes and no serious attacks were reported.

Violence is common among Russian football fans, and Spartak fans -- known as Gladiators -- have been implicated in other xenophobic attacks in recent years.

In October, teenage Spartak fans were detained after a wave of knife and other attacks left several dark-skinned foreigners dead.

In an apparently unconnected attack, a Nigerian student was in the hospital with a concussion on Monday after being attacked by four drunken factory workers near the Prazhskaya metro station, Itar-Tass reported.

The student, from Peoples' Friendship University, was not identified.