KUALA LUMPUR, MALAYSIA - MALAYSIAN authorities said they were investigating how a man boarded a plane with a knife that he pulled out mid-flight, causing panic among passengers.

The pilot of the flight from Kuala Lumpur to Dhaka made an emergency landing on Tuesday morning in Bangkok, though officials disagreed over whether the man had brandished the knife in a threatening manner or just wanted to peel an apple.

'Malaysia Airports is currently conducting a thorough investigation into this incident,' said head of security Kamaruddin Mohamad Ismail.

'The security officer on duty has been suspended pending further investigation,' he said in a statement on Wednesday.

Malaysia Airports manages the sprawling Kuala Lumpur International Airport complex in the outskirts of the city.

Sharp objects, including knives, nail files and scissors are not allowed into planes, and passengers checking-in through the airport are routinely checked by security officers, using a metal detector.

Hand-held bags are also scanned by officers.

Officials said that Tuesday's incident was not a hijacking or a terror act and that the passenger, a Bangladeshi national, had only taken out the knife to cut an apple.

However a Thai official said earlier that the pilot of the GMG flight acted after the man had been unruly and had frightened other passengers.

The Bangladeshi plane, with about 60 people on board, made an emergency landing at Bangkok's domestic Don Muang airport and was grounded for about two hours before resuming its journey to Dhaka.

The man was later released to board a flight to Dhaka on Tuesday evening, Malaysia Airports said. -- AFP