The students have called for the sit-ins Monday, 10 days after the police shooting death of a 15-year-old boy sparked nationwide riots in which at least 70 have been injured, stores and international businesses attacked and at least 280 people detained, CNN said.

Protesters say Monday's sit-ins are to take place in front of Greece's national police headquarters in Athens, as well as in front of police precincts across the country, the U.S. broadcaster said.

Violence continued Saturday night, with youths throwing petrol bombs at banks and at the police station where the officer charged with the teenager's killing was based, the BBC reported, saying police responded with tear gas.

Saturday's clashes appeared to pick up in intensity over those of the last few days, observers said.