Anarchists have burnt a public transport bus and several cars in central Athens during clashes with police.

The violence followed a large demonstration Tuesday in support of a jailed anarchist who is on hunger strike seeking prison leave to attend university.

Riot police fired tear gas to dispel stone-throwing rioters, but no arrests or injuries have been reported.

Between 8,000 and 10,000 people earlier marched through central Athens in solidarity with Nikos Romanos, a young anarchist convicted of involvement in an armed bank robbery.

He has refused food for the past three weeks after authorities said they wouldn't let him attend lectures at an Athens university, where he was admitted after being allowed to sit entry exams in prison.