ANKARA - Turkish police used tear gas to disperse about 5,000 anti-government protesters in the Turkish capital of Ankara on Saturday night as the nationwide protests entered the 12th day, witnesses said.

The witnesses said the Turkish police first warned the protesters in Kizilay Square and later used tear gas and water cannon to disperse them.

Earlier in the day, the semi-official Anatolia news agency said that Turkey has launched a probe into the "physical violence" used by policemen against protesters in the Aegean city of western Izmir province during last week's demonstration.

Turkish people have protested against the demolition of Taksim' s Gezi Park, which turned into clashes between police and protesters.

The anti-government protests have spread to 67 provinces, including Ankara and coastal cities of Antalya and Izmir. The clashes have led to three people dead, more than 4,000 injured and thousands detained.

On Wednesday, organizers of the protests said that they will continue their "struggle" until their demands are met by the government through tangible steps.