Thousands of anti-government demonstrators have picketed the US embassy in Bangkok reports news agency AFP. The so-called Red Shirts accuse US intelligence of bugging former prime minister Thaksin Shinawatra.

The picket comes after Prime Minister Suthep Thaugsuban told the media that foreign intelligence had warned of violence. He did not mention the US specifically. The Red Shirts, who support the former prime minister, left after submitting a letter demanding an explanation from the embassy.

Earlier Thaksin supporters poured litres of blood onto the ground outside the Prime Minister Abhisit Vejjajiva's heavily-guarded residence and the government headquarters.

Thousands of demonstrators, many of whom have traveled from rural parts of the country in the north and east, have been on the streets of the capital since the weekend. On Tuesday, many gave blood to symbolically show they are prepared to spill “blood for democracy” in Thailand. The Red Shirts are demanding the government stand down and call early elections.