An onlooker was also shot in the head with a stray bullet, a photographer from the Associated Press reported.
 
The man showed no signs of life, television footage showed. It is unclear whether the man died from his injuries.

'Attacks planned'

Automatic gunfire and sporadic blasts were heard as the raid went ahead, and tear gas was used by the police, witnesses said.

The police had raided more than 60 areas overnight in an attempt to crack down on armed groups alleged to be planning attacks on public targets.

"They were planning to stage sensational armed attacks soon," Guler said.

"We have seized lots of weapons, bombs and booby traps."

Turkey has in recent years focused its efforts on tackling members of the Kurdistan Workers' party (PKK), a group fighting for greater autonomy for the Kurdish community.

But several armed left-wing and radical religious groups are also active across the country.

The police raids came days before May Day, when the authorities are usually put on alert for possible clashes with opposition groups.