Officials said the violence was waged mostly by a group of hooligans, including football fans and masked rioters, who began throwing firecrackers, petrol bombs and rocks at police officers and parked cars.

Others set fire to trees and garbage containers.

Broadcast images also showed rioters attacking police officers with metal rods. Police responded with tear gas and water cannon. At one point, the scene devolved into street fights. Calm was not restored until early on Wednesday.

Speaking on state television, a police spokesperson said one of the police officers was badly injured, but was no longer in danger of dying.

Greek Prime Minister Kyriakos Mitsotakis was joined by opposition party members in condemning the violence.

"This blind violence doesn't lead anywhere," said Mitsotakis, also speaking to state television.

The original demonstration was a response to a case of police violence on Sunday, when police in the Athens suburb of Nea Smyrni were caught on film kicking and beating, with both fists and batons, a man.

The incident apparently started during a stop in relation to the country's coronavirus restrictions.

Prosecutors and the government have called for an investigation. The government has also criticised the police in the case. There has also been an outpouring of anger on social media.

Australian Associated Press