A RIA Novosti correspondent also reported that new clashes between demonstrators and police had begun in Athens.
Trouble originally began after a policeman shot dead a 15-year-old boy in Athens last Saturday. Two police officers have been detained over the killing.
Epaminondas Korkoneas, 37, was charged on December 7 with murder and illegal use of his weapon. His lawyers said on Wednesday that ballistics results had established that Korkoneas acted in self defense, and that the boy was killed by a ricochet. Eyewitnesses maintain that the officer took aim at the victim before firing his weapon.
The second officer, Vassilios Saraliotis, 31, was charged with abetting his partner.
Some 6,000 people attended the teenager's funeral on Tuesday in a southern suburb. The ceremony was relatively calm but later police used tear gas to disperse youths as violence erupted outside the cemetery when groups of teenagers started throwing stones.
Thousands took to the streets of the Greek capital on Wednesday as a nationwide strike brought the country to a halt.
The planned 24 hour strike hit public transport and flights, closing banks, schools and universities as trade union members and demonstrators gathered outside the parliament to protest government economic policies and demand the resignation of Prime Minister Costas Karamanlis.
