Passengers at Suvarnabhumi Airport look on as officials spend nearly three hours searching a Thai Airways aircraft, following an alleged bomb threat yesterday. The inspection found nothing unusual.

Officials undertook an intensive search of the plane, flight TG 521 bound for Dubai via the south Indian city of Chennai, but no explosive was found on the aircraft.

Sunathee Isvarphornchai, THAI's vice president for corporate communications, said authorities learnt of the threat just before the flight was due to leave Bangkok, at 10.55am yesterday.

A female passenger - later identified as Padmapriya Natarajan, 29, from India - told airline staff just before boarding she had received a call on her mobile phone before boarding. A female voice had allegedly asked if she "knew Bin Laden" and told her a bomb had been planted on the plane TG 521, Sunathee said.

Thai Airways officials plus police and bomb squad officials spent nearly three hours searching the aircraft, passenger luggage and cargo but found nothing unusual, she said.

However, the airline decided to fly the 270 passengers and 18 crew members to the scheduled destination on another aircraft. The flight departed at 3.30pm, but Natarajan was held for further questioning.

Immigration Police deputy superintendent Lt Col Phakkapong Sai-ubol said Natarajan had both Indian and Canadian nationalities and presented a Canadian passport to immigration police at the airport.

Police suspected Natarajan had either made up the bomb threat or received the call from friends who wanted to tease her, as the call was made to her personal phone.

At press time, police were still questioning Natarajan at Samut Prakan's Rajathewa police station.

If the investigation discovers she has lied, police could place her on a national security-related charge, said Lt Col Phakkapong. But if she was found to have done nothing wrong, she would be allowed to leave for Dubai on the next flight.