Six Greek police officers were wounded, two seriously, after gunmen opened fire on a police station late Tuesday in the suburbs of the Greek capital, reports said.

Four hooded gunmen opened fire with rifles on the Agios Pareskevis police station, injuring six police officers, two of whom were in serious condition.

Three or four unidentified persons opened fire with AK- 47 assault riffles against a police station in the northern suburb of Aghia Paraskevi around 10:00 p.m. local time, as officers changed shifts.

They escaped on two motorcycles, according to witnesses, after having fired around 90 shots.

The officers were rushed to hospital where two of the officers who suffered gunshot wounds to the stomach and chest were undergoing emergency surgery.

Greek President Karolos Papoulias condemned the terrorist attack at an Athens police station on Tuesday night, in which six policemen were injured, according to the latest information.

"I condemn this coward terrorist act that has endangered human lives," the president said in a statement released from Thessaloniki, where he has traveled to attend Wednesday's national day military parade.

There was not immediate claim of responsibility for the shooting, but police sources point to two guerrilla groups which have made similar attacks on Athens police stations, Revolutionary Sect and Revolutionary Struggle.

Local militant, anarchist and far Left groups have stepped up attacks against police officers, political and financial targets, big business institutions and foreign enterprises since massive riots that broke out last December, after the death of a teenage boy in a police shooting.

An anti-terrorism officer guarding a witness' home in Athens was killed on June 17. The group Revolutionary Sect claimed responsibility for that attack.