Nine people were arrested late Thursday after clashes in which several police officers were hurt during an Athens protest against a new law regulating demonstrations in Greece, police said.
Police fired tear gas at the protest outside parliament and charged at demonstrators after a small group of masked youths broke away to throw firebombs.
Six police officers were injured, according to the authorities.
That protest and others had been called days before in anticipation of the new law being adopted by parliament late on Thursday.
The main opposition Syriza party said the police used undue force against a largely peaceful demonstration.
Police said some 12,000 people took part in a number of separate protests in Athens Thursday called by leftist and communist parties against the demonstration law.
Among the new regulations are less street space afforded to smaller protests and the right of police to ban certain gatherings — including counter-protests — for security reasons.
Prime Minister Kyriakos Mitsotakis said the new rules were necessary to regulate “dozens of small protests” that routinely shut down city centres.
The law was approved late Thursday by 187 votes in favor out of 288 lawmakers present.
Opposition parties have accused the government of seeking to muzzle criticism ahead of a deep recession coming in the autumn, exacerbated by a long coronavirus lockdown.
Amnesty International also expressed “serious concern” about the new law, arguing that it runs counter to international human rights provisions.