BANGKOK: Thai authorities have tightened security measures at the US Consulate in the northern province of Chiang Mai following reports that it was a possible target of attack from Al Qaeda and Salafist terrorist groups this month, officials said Tuesday.    

Prime Minister Yingluck Shinawatra told reporters she had been informed about the reports and that she had ordered security agencies to add more forces to provide safety at the facility, 570 kilometers  north of Bangkok.

''The US Embassy in Thailand has not requested any extra measures but we have to monitor the situation attentively,'' Yingluck said.

Deputy Prime Minister Chalerm Yubumrung refused to give details about the threats, but said the reinforced measures had been put in place since Feb 6 and will continue until the end of multinational military exercises, called Cobra Gold, on Sunday.

''They are focusing on staging an attack during the Cobra Gold exercise,'' Chalerm said. ''Some might have come to the country as tourists, but we have in-depth information and are definitely following them.''

Chalerm said that some of the groups' members have fled Thailand after knowing that authorities had learned about their plots. ''Some of them remained here, but I believe they can't carry out any attacks.''

The United States is among the seven nations participating in the exercises, which kicked off on Monday in Chiang Mai. The other countries involved are Indonesia, Japan, Malaysia, Singapore, South Korea and Thailand.

Chalerm said the reports came from domestic sources and were deemed ''dangerous.''

''There are several reasons (for the warning) but I must keep them confidential,'' Chalerm told reporters.

US Embassy spokesman Walter Braunohler in Bangkok said the US Consulate-General remained open for business but said precautions will be taken to protect US facilities.

''We continue to take every precaution to protect our facility, whether it's in Bangkok, Chiang Mai or worldwide, our employees and our visitors,'' Braunohler told The Associated Press.

Thailand has not been a major target for terrorism attacks, although in January 2012 the US and the Israeli embassies sent out warnings of a possible terror threat in the capital, which in the end saw the arrest of a Lebanese-Swedish suspect accused of possessing nearly 3,000 kilograms of ammonium nitrate, a fertiliser that can be used to make explosives.

A month later, two Iranian suspects were detained following an explosion on Valentine's Day that saw four civilians wounded. The blast came a day after an Israeli diplomatic car was bombed in India, an attack Israel blamed on Iran.

Thailand is a long-standing partner of the United States and major non-Nato ally.