Police yesterday were investigating the motives behind a grenade attack on the premises of a left-wing human rights group and immigrant support network in the central Athens district of Exarchia, which caused no injuries and only limited damage after the grenade bounced off a window and detonated on the sidewalk. The attack took place late on Tuesday night when some 25 people were holding a meeting in the premises of the Network for Political and Social Rights, which has the same address as the so-called Immigrants Hangout. An unidentified assailant hurled a hand grenade that bounced off a ground-floor window and exploded on the ground, causing minor damage to the building and an adjacent bar. Witnesses in the street reported seeing a man with a shaven head fleeing the scene in a blue car. The leftist network yesterday issued a statement referring to «a fascist para-state murder attempt that is part of a general effort by the establishment to stage a counterattack in response to the December uprising.» A spokesman for the network claimed that it had been targeted by rightists since the December riots and accused of covering up for self-styled anarchists. There have also been accusations of links between Exarchia-based leftists and terrorist networks, he added. Police, who said they received no warning or claim of responsibility for the attack, did not corroborate suspicions of a far-right connection, suggesting instead that the hit could have been carried out by members of anarchist or far-left groups who have differences with the leftist network. Forensic experts yesterday were examining the remains of the Soviet-era hand grenade. There has been no suggestion that the attack might have been racially motivated.