Opposition protesters and police have clashed in the main tourist area of the Thai capital Bangkok.

No one was injured and tourists in the area were apparently not perturbed. About 20,000 "Red Shirts", supporters of ousted former prime minister Thaksin Shinawatra, have been camping out in the main shopping and hotel district of Bangkok. They are demanding the resignation of Prime Minister Abhisit Vejjajiva's government.

The protesters have been surrounded by riot police, but the authorities have promised they will not resort to violence. Earlier today. two police officers guarding the headquarters of the ruling Democrat Party were injured when a grenade was fired into the compound.