Greek police said an officer received serious head injuries as clashes broke out Tuesday evening at a protest of some 5,000 people in Athens against police violence.

Two other officers were also hurt at the demonstration, which follows an uproar over viral video footage that showed an officer beating a man with a baton Sunday during a patrol to enforce a coronavirus lockdown.

An AFP photographer at the scene of Tuesday's protest said clashes broke out after a group of around 200 masked protesters headed towards the police station in Nea Smyrni, the calm southern Athens suburb where Sunday's beating had taken place.

Dustbins were set ablaze as the demonstrators threw rocks and Molotov cocktails at a police station, AFP reported. Police responded with tear gas and water cannon.

The protest followed months of anger in the Greek media and among campaigners over numerous high-profile cases of alleged police brutality at student and left-wing protests.

Police said the injured officer was rushed to hospital after he was pushed off his motorbike and beaten by protesters
Police said the injured officer was rushed to hospital after he was pushed off his motorbike and beaten by protesters AFP / Louisa GOULIAMAKI

Police said the badly injured officer, who was seen being dragged off his motorbike and beaten by protesters.

He was rushed to hospital and the ANA news agency reported that his life was not in danger. Ten protesters were detained, police said.

In a statement, Prime Minister Kyriakos Mitsotakis asked people to ensure that "the sad images of violence that we have seen in Athens this evening are the last".

"I will not allow anyone to divide us," he said, while left-wing opposition party Syriza condemned "those who tarnished a peaceful protest" by turning to violence.

Police said the injured officer was rushed to hospital after he was pushed off his motorbike and beaten by protesters
Police said the injured officer was rushed to hospital after he was pushed off his motorbike and beaten by protesters AFP / Louisa GOULIAMAKI

According to the police, around 5,000 people overall took part in Tuesday's demo against police brutality, some holding banners which read "cops out of our neighbourhoods" and "parks are for laughing, not for hearing the words 'I'm in pain'".

The latter was a reference to the viral video footage showing a young man shouting "I'm in pain" as he was beaten Sunday at the Nea Smyrni square, a popular spot for family gatherings.

Onlookers can be heard in the footage expressing outrage at the police officer behaving this way in front of their children.

Police said they had been called to Nea Smyrni on Sunday after receiving numerous complaints about people violating Covid-19 restrictions by sitting out on the square.

Athens residents are currently under stay-at-home orders -- with only essential trips allowed -- in a bid to tame the coronavirus pandemic, which has claimed some 6,800 lives in Greece.

The Efsyn newspaper published an interview Tuesday with the man who was beaten, identifying him as a 29-year-old student named Alexandros.

He told the paper that police had wanted to fine families 300 euros ($360) for sitting on the square in breach of the lockdown, and that he had tried to reason with the officers.

"A policeman then came towards me and targeted me," Alexandros told Efsyn. "He pushed me and then the other officers kicked me all over my body."

Police said they had been attacked during the weekend incident by "30 people who injured two of our agents" -- a claim local residents have denied.

Prosecutors have ordered a preliminary investigation into the man's beating, according to a legal source. Police have also opened an internal probe into the officer filmed hitting him.