Thai authorities received a tip-off before New Year of a planned attack, which was said to target Israelis, Deputy Prime Minister Chalerm Yubamrung said.
Police on Thursday detained one of two suspects from Lebanon with alleged links to Hezbollah. He was held under immigration laws, and was being interrogated.
Chalerm spoke hours after the US Embassy in Bangkok sent an “emergency message” to American citizens yesterday 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 exercise caution in areas where Western tourists gather.
It was the first US warning of a foreign terror attack in Bangkok in recent memory.
Hezbollah, a Shiite Muslim militant group, is backed mainly by Iran and Syria and is strongly anti-Israel. The terror 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.