The flight was stopped at Jinnah International airport, Pakistan's busiest gateway in the southern city of Karachi, when heavily armed militants attacked one of the terminals, leaving 23 people dead.
THAI acting president Chokchai Panyayong told a Thai television programme Monday morning that flight TG508 was bound for Bangkok from Muscat in Oman.
Its 296 passengers, 16 flight crew members were safe in the transit area. The attack occurred at a different terminal, he said.
As a commercial flight, TG508 made the stop at a terminal quite a distance from the one that was attacked.
He said three of the passengers were Thais.
According to Airports of Thailand hotline, TG508 has been delayed until further notice. Its scheduled arrival time in Bangkok was 6.40am Monday.
Based on the latest update by Kyodo News, the attack left 23 people dead and one aircraft on fire.
The casualties included 10 militants who were killed in a gun battle with security forces. The military cordoned off the area and sealed all roads leading to the airport.
The Japanese news agency said the fireflght occurred near the terminal for Haj piligrims several kilometres from the main passenger terminal.