Police, rioters clash in Greece as nation goes on strike...

On Athens' central Syntagma Square outside the parliament building, police used tear gas to clear some of the 20,000 protestors, who included some 300 anarchists, after firebombs were thrown at them, an AFP reporter said.

At least two protesters were injured, the ambulance service said, in addition to an AFP photographer struck in the face by a riot policeman's shield as she took pictures of his colleagues hitting a demonstrator lying on the ground.

Another 10,000 people marched in the northern city of Thessaloniki.

The protests organised by the two main Greek unions, ADEDY and GSEE, came ahead of a general strike on October 19, which will also affect banks and shops.

It was called in response to new taxes, wage cuts and layoffs imposed by a government, fighting to avert a default on its debt payments, as the next installment of international aid hangs in the balance.