Deputy Prime Minister Chalerm Yubamrung said Thai authorities received a tip-off before New Year's Day 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 Hezbollah," he told The Associated Press.

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.

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.

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