Wednesday, September 1, 1999 Published at 09:33 GMT 10:33 UK
Note found at blast scene
Women were among the injured
Russian security forces are investigating an explosion which ripped through an underground Moscow shopping centre on Tuesday night, injuring 40 people.
A note was found at the site of the explosion from the group, calling itself the Revolutionary Writers.
"Philistines, we don't like your way of life," it said.
The explosion showered an adjacent row of fast food restaurants with broken glass and metal shards, injuring dozens of tourists and late-night shoppers.
The note from the Revolutionary Writers said: "A hamburger not eaten to the end by the dead consumer is a revolutionary hamburger," the FSB said.
Officials said they had not heard of the group before.
Fears of return of terrorism
The explosion has triggered fears of terrorism returning to Russia.
Russian media have suggested it might be linked to Islamic militants who are waging war against Russian rule in the Caucasus or to political battles in Moscow itself.
The BBC's Paul Anderson in Moscow says the proximity of the blast to the offices of President Yeltsin also gave rise to suggestions that it may have been connected to the political battles currently being waged ahead of parliamentary elections later this year.
Russian media also said the victims could have been caught up in the violent settling of scores between rival Mafia groups.
Russia has scores of bomb attacks each year, often involving organised crime groups or business rivals seeking to settle turf battles.
President Boris Yeltsin, who was at one of his country homes outside Moscow when the blast hit, expressed shock and offered his condolences.
Moscow Mayor Yuri Luzhkov called the blast a "terrorist act."
The mayor, who oversaw the construction of the shopping centre as one of the main focal points of his campaign to modernise the city, said the people who planted the alleged bomb were "beasts".
The three-floored shopping centre - one of Europe's largest malls - was opened in 1997 as part of Moscow's 850th anniversary celebrations.
This was the second major explosion to rock the Russian capital this year.
Eleven people were injured in an explosion at Moscow's Intourist hotel in April.