Police in Thailand are questioning a suspected Hezbollah member, with the development coming as the US embassy warned American nationals of the threat of a terrorist attack in the country.

The suspected Hezbollah member, a Lebanese man, was arrested on Thursday after a tipoff from Israel about a potential attack in Bangkok, the Thai deputy prime minister, Chalerm Yoobamrung, said, adding that police had stepped up security.

Chalerm told Reuters: "A Lebanese suspect from the Hezbollah group has been taken into custody by Thai officials and police are investigating further.

"Following concern raised by the Israeli embassy about a possible attack by a group of Lebanese terrorists in Bangkok, Thai police officials have been co-ordinating with Israeli officials since before the new year."

He said the authorities had been following two Lebanese men, but did not say what had happened to the other, and also suggested that Thailand had no strong evidence linking the men to a planned attack.

"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.

On Friday, the US embassy issued an emergency message warning that "foreign terrorists may be currently looking to conduct attacks against tourist areas in Bangkok in the near future. US citizens are urged to exercise caution when visiting public areas where large groups of western tourists gather in Bangkok".

Thailand's defence minister, Yuthasak Sasiprapha, said: "Thai officials had not intended to release the news at this time, since it could have an impact on tourism and cause panic among citizens."

He added that the US embassy was naturally concerned about its citizens, and said Thai and US intelligence officials were monitoring other individuals. The authorities were applying extra precautionary measures in areas popular with tourists as well as Suvarnabhumi airport in Bangkok, he added.

Yuthasak identified the Israeli embassy and synagogues as possible targets, while adding that intelligence reports said the planned attacks might be related to US activities against Iran.

Iran has blamed the US and Israel for a series of assassinations of its nuclear scientists, the most recent of which was on Wednesday. According to Iranian news sources, Mostafa Ahmadi Roshan was killed in Tehran when two men on a motorcycle detonated a bomb attached to his car.

Hezbollah, a militant Shia Muslim group accused of carrying out terrorist attacks in the Middle East since the 1980s, is backed by Iran and is widely considered to be a proxy for the Tehran regime.

Reuters reported a Thai defence ministry source as saying that Israeli intelligence had contacted Thai officials on 22 December with information that two or three suspects could be planning an attack in Thailand. However, the individuals travelled to the south and left the country.

On 8 January, the Israelis again warned Thai officials of the danger of an attack between 13 and 15 January in areas where there are often large concentrations of western tourists such as the Khao San Road, which is popular with young backpackers. Thailand is also a popular destination for young Israelis holidaying after completing their military service.

Thailand has rarely been a target for foreign terrorists, although domestic militant Muslim groups are engaged in an insurgency in the south and have bombed civilian targets. Last month, six homemade bombs were found in Bangkok and a man was arrested.

The UK Foreign Office's travel advice warns of "a high threat of terrorism … including in places visited by expatriates and foreign travellers". A spokesman said the level of advice had not changed since December.