By Santanu Choudhury 

NEW DELHI--A Turkish Airlines passenger jet Tuesday made an emergency landing at Delhi's international airport following a bomb threat, an airport spokesman said.

The aircraft was over Indian airspace on a scheduled flight from Bangkok to Istanbul when the crew discovered a message on a mirror in the bathroom, which said that there was a bomb in the cargo hold and requested an emergency landing, the spokesman said. The plane was carrying 134 passengers, Turkish Airlines said in a statement. It did not say how many crew members were on board.

The Airbus 330 aircraft landed safety at the Indira Gandhi International Airport and was immediately taken to an isolation bay where it is being checked for any explosives, the spokesman said. The plane was evacuated on landing, the airport spokesman said.

"There is no information so far about any explosives on the aircraft," the spokesman said.

Bomb disposal and dog squad teams were thoroughly examining the aircraft and a final decision on the fate of the aircraft would be given only after checks were complete, said a spokesman for India's Central Industrial Security Force, which provides security at the airport in Delhi.

Turkish Airlines confirmed in a statement that its TK0065 flight from Bangkok to Istanbul was diverted to Delhi following "a possible bomb threat on board."

"All of our passengers and cabin crew have been evacuated safely and taken to the terminal building," the statement said.

The statement said safety checks were taking place and once they were complete, the plane would continue its journey to Istanbul.

The carrier has made at least four emergency landings due to bomb scares since late March, diverting two flights back to Istanbul while one plane landed in Copenhagen and another in Casablanca. No explosives were found in any of the instances, which involved flights to Tokyo, São Paulo, New York and Basel, Switzerland. The interrupted flights that didn't return to Turkey continued to their final destinations after security checks.

Vibhuti Agarwal and Emre Peker contributed to this article.

Write to Santanu Choudhury at santanu.choudhury@wsj.com

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