BANGKOK — Thai police were on Friday questioning a Lebanese man with alleged links to Hezbollah militants as the US Embassy warned of a "real and credible" threat of a terrorist attack against American citizens in Bangkok.

The warning comes during a period of heightened tension over US and Israeli responses to the prospect that Iran is going forward with developing nuclear weapons. Lebanon-based Hezbollah, which has been accused of carrying out terrorist attacks in the Middle East since the 1980s, is avowedly anti-Israel and widely considered to act as a proxy for Iran.

Deputy Prime Minister Chalerm Yubamrung said Thai authorities received a tip-off before New Year's of a planned attack, which was said to target Israelis.

"At first we were told the Palestinians were behind it but it turned out to be the Hezbollah," he told The Associated Press. He did not say who provided the tip-off.

He said police detained on Thursday a Lebanese suspect with alleged links to Hezbollah.

Thai authorities had been "following two Lebanese men and called in one of them ... for questioning," Chalerm said. "Technically the two men have not committed any crimes under the Thai law, so we could only use the immigration law to keep this one suspect in custody," he said. He was not clear on what happened to the second suspect.

Chalerm spoke hours after the US Embassy in Bangkok sent an "emergency message" to American citizens earlier Friday warning of a possible terrorist attack.

The message said that "foreign terrorists may be currently looking to conduct attacks against tourist areas in Bangkok in the near future." It urged Americans to "keep a low profile" in public and to exercise caution in areas where Western tourists gather.

The statement gave no other details.

Ambassador Kristie Kenney told the AP the threat was "real and very credible." She didn't give any other information.

It was the first US warning of a foreign terror attack in Bangkok in recent memory.

Chalerm said the danger has passed.

"I want to confirm and I am confident that we have the situation under control. And I can guarantee ... no terrorist attacks will be allowed to take place. If they have disagreement, (they should) go fight somewhere else."

Thai Defense Minister Yuthasak Sasiprapa also gave an account of the alleged plot, saying preliminary intelligence suggested that an attack would be carried out between Jan 13 and Jan 15. He told reporters that keeping track of the suspects had been difficult, and if they had not been found by 6 pm Friday, there would have been "an escalation of security measures." He did not explain further what that entailed.

Yuthasak said Thai authorities had not released news of the alleged plot because it would hurt the tourist industry and cause panic among the public. He said intelligence reports said the planned attacks might be related to the US activities concerning Iran.

Iran sees possible US complicity in a series of assassinations of its nuclear experts — the latest Wednesday, when scientist Mostafa Ahmadi Roshan was killed by a bomb attached to his car by a passing bicyclist.

Hezbollah, a Shiite Muslim militant group, is the most potent military force in Lebanon, far stronger than even the national army. It is backed mainly by Iran and Syria.

Thailand has rarely been a target for foreign terrorists, although domestic militant Muslim groups are engaged in an insurgency in the country's south and have bombed civilian targets.

In 1994 there was an abortive attempt to bomb the Israeli Embassy in Bangkok. It was abandoned when the driver of the truck, which had been turned into a massive car bomb, fled after a minor traffic accident. Several Iranians were arrested in connection with the attack, but all were eventually released.

There have been several reported plots against the US Embassy in Bangkok in the past two decades, but no attacks.