Two police officers were injured in the central Athens district of Exarchia when they were attacked by a group of about 30 people on Tuesday night.
The police said that five officers were on a foot patrol at the corner of Themistokleou and Eressou streets when they were set upon. Their attackers were wielding rocks and pieces of wood, police said.
One officer was hit on the head with a hammer. It was not clear how the other policeman was injured.
They were both taken to the hospital to be treated for their injuries.
The foot patrol called in backup but officers were not able to make any arrests.