A Singapore Airlines (SIA) flight from Mumbai landed safely at Changi Airport yesterday morning, after the pilot raised a bomb threat alert.

A search of the plane found no suspicious item, the police said.

SQ Flight 423 was escorted safely back to Changi Airport by two F-16 fighter jets from the Republic of Singapore Air Force (RSAF).

After the plane touched down at about 8am, all passengers, except a woman and a child, disembarked safely and had to undergo security screening before they could leave.

The Straits Times understands that the woman and the child were held back for questioning.

SIA had received a call after the aircraft left Mumbai's airport on Monday at about 11.35pm local time. The caller claimed there was a bomb on the plane.

An SIA spokesman told The Straits Times: "We are assisting the authorities with their investigations and regret that we are unable to provide further details."

The Boeing 777-300ER aircraft had 263 passengers on board. More than 20 people missed their connecting flights.

Major Jireh Ang, 32, a fighter pilot from the 143 Squadron, said that on being notified of the threat at 7.04am, the two fighter jets were scrambled within minutes.

"It was only when we were airborne that we received details and further orders of the mission. Our regular and rigorous training has ensured that we are always ready for the task when called upon," he said.

The RSAF works with other national agencies to monitor the Singapore skies and respond swiftly and decisively to any potential air threats on a 24/7 daily basis, he said.

"Once we had successfully intercepted the Singapore Airlines aircraft, we established communications with the pilots through the assigned radio frequency.

"We informed that they were being escorted by the RSAF fighters and for them to comply with all instructions.

"We also got the pilots' visual attention, and at the same time, we were able to observe if there were any abnormal activities within the cockpit and the cabin," he said.

The last such incident involving a Singapore carrier occurred in April last year, on a Scoot flight bound for Hat Yai, Thailand.

A passenger, unhappy about being told he had to check in his carry-on bag, joked he had a bomb in the bag. The plane made a U-turn, with fighter jets from the RSAF scrambled to escort it back.

Last October, Hsu Chun Meng was fined $4,500 for breaching the Protection from Harassment Act by using threatening words to cause alarm.