Tbilisi: Georgian police fired tear gas and water cannon on Wednesday to break up a six-day protest calling on pro-US President Mikhail Saakashvili to resign.

Riot police wearing gas masks and using batons and shields charged an area outside the parliament where around 3,000 demonstrators had gathered, chasing them through the streets.

A truck armed with a water cannon sprayed the protesters and police wearing body armour moved in formation down the streets firing tear gas.

The demonstrators fled, tripping over each other to escape the gas. Some could be seen being dragged bleeding into police cars. Ambulances sped through the streets, their sirens wailing.

Earlier opposition leaders had urged supporters to mass at 2 p.m. in force outside parliament, defying police moves in the morning to break up their six-day long protest.

"Shame on you Mikhail Saakashvili," opposition leader Zviad Dzidziguri shouted down a microphone. "You are afraid of your own people, you are a coward."

Police hit some of the protesters with batons when they cleared about 100 demonstrators from outside parliament at 8 a.m., an opposition leader told Reuters.

"There were about 1,000 police," opposition leader Tina Khidasheli said. "They beat us and detained two people, as far as I know."

Georgia, a former Soviet republic, lies at the centre of the Caucasus region -- a volatile area to the south of Russia which hosts a pipeline pumping oil from the Caspian Sea to the West.