The 15-year-old boy's shooting death on Saturday triggered the most violent riots in the country in a quarter century which have dealt a major blow to the country's increasingly unpopular conservative government.
Hundreds of demonstrators threw petrol bombs and other projectiles at the police on Tuesday, before riot police charged to push them back towards Syntagma square in Athens.
1974 - Student uprising leads to the end of seven years of brutal military dictatorship. Police banned from entering university campuses.
1981 - A socialist government comes to power, rules for 23 years.
2004 - Conservative leader Costas Kara-Manlis elected. His administration becomes increasingly unpopular, for its handling of the 2007 deadly summer fires, a land swap scandal and frowing dissatisfaction with social and economic reforms.
The central square had been the scene of violence on Monday night when rioters torched shops, government ministries and banks.
The killing of Grigoropoulos has touched a raw nerve among young Greeks, angry at years of political scandals and rising levels of poverty and unemployment, worsened by the global economic downturn.
Stathis, the police spokesman, said 89 people had been arrested for attacks on police, vandalism and looting since the violence began.
Another 79 people had been detained for questioning over the riots in which dozens of police officers have been injured.
At Grigoropoulos's funeral at the municipal cemetery of Palio Faliro, a residential suburb in southern Athens, some groups shouted anti-police slogans but it was mainly calm after a request from the family that respect be shown for the dead teenager.
Earlier, Karolos Papoulias, Greece's president, had appealed for calm, calling on Greeks to "honour Alexis' memory peacefully".
"This is a day of mourning for us all... but there must be respect for institutions and laws," Papoulias said in a statement.
Two officers have been charged over the shooting - one with premeditated manslaughter and the illegal use of a weapon and the other as an accomplice.
They are due to appear before a court on Wednesday and both have been suspended - along with the Exarchia precinct police chief.
Government under pressure
Demonstrations and violence played out in similar ways in other cities across the country as George Papandreou, the Socialist opposition leader, demanded that the conservative government step down and call elections to help end the violence.
|Protesters threw fiery projectiles at the
police outside parliament [AFP]
Addressing his parliamentary group on Tuesday, Papandreou said: "We claim power. The only thing this government can offer is to resign and turn to the people for its verdict."
Costas Karamanlis, Greece's prime minister, has vowed to end the country's worst unrest in decades, but a government spokesman denied reports that the government planned to declare martial law.
Greek labour unions rejected an appeal by Karamanlis on Tuesday to cancel a mass protest planned for Wednesday to avoid further violence.
"Our answer is that the strike and the rally will take place as planned," said Stathis Anestis, spokesman for GSEE, Greece's largest labour confederation.
The 24-hour nationwide strike and rally, which was arranged before the shooting took place, is taking place to protest against the government's economic policies and reforms.