The US embassy in Thailand warned on Friday that "foreign terrorists" could be looking to conduct attacks in areas of the capital, Bangkok, frequented by toursts and told its citizens in a message to be careful.

Walter Braunohler, spokesman at the embassy, declined to give further details but said: "We're warning all US citizens to take caution when visiting public areas where Western tourists are known to gather in Bangkok."

Bangkok, a magnet for tourists with its vibrant nightlife and a transit point for those heading for Thailand's beaches, has faced political turmoil in recent years but threats of foreign attacks are rare.