Anti-austerity protesters and police clashed on Thursday outside parliament where lawmakers debated further spending cuts demanded by the country's international lenders in exchange for bailout funds.
A small group of hooded protesters broke away from a rally of about 10,000 demonstrators and hurled petrol bombs and firecrackers at police officers guarding parliament.
Police responded with tear gas dispersing the crowd temporarily.
As clashes broke out, Prime Minister Alexis Tsipras was delivering a speech in parliament defending proposed legislation which could be adopted later on Thursday.
TRT World spoke to Maria Kagkelidou in Athens.
The proposed austerity measures include pension cuts and tax hikes to be implemented in 2019 and 2020.
A vote was expected around midnight local time (2100 GMT).
Tsipras' coalition came to power in 2015 promising to end austerity but it was forced to sign up to a third bailout later that year.
The ruling coalition has a slim majority of 153 lawmakers in the 300-seat parliament.
The leftist-led government hopes that legislating the measures, four days before Euro zone finance ministers meet in Brussels, will convince its lenders to release a €7.5 billion bailout tranche and grant it further debt relief.