A pilot of a Saudi Arabian Airlines flight accidentally pressed a hijack alarm, triggering a major security response at Manila airport on Tuesday, authorities said.
Police isolated and surrounded the Saudia flight after it landed on Tuesday afternoon just after one of its pilots released a distress signal indicating a hijack incident was underway, the Philippine aviation authority said in a statement.
Hundreds of passengers aboard the Boeing 777 flight from the Red Sea city of Jeddah were forced to remain on the plane for more than two hours, but were let off about 5:00pm (0900 GMT) after it was confirmed there was no threat.
"Situation is normal. It was alleged that the pilot pressed the emergency light of the aircraft unintentionally," Manila police chief Oscar Albayalde told reporters.
In Saudi Arabia, an airline spokesman also told AFP there was no security threat.
"False alarm for hijack for Flight 872," the spokesman said.
The aviation authority statement said the distress signal pressed by the pilot alerted authorities "that a hijacking incident is on progress on board".
"Immediately the flight was given priority landing by airport authorities... and was directed to park on the remote bay and isolated for security procedures," the statement said.
"Apparently the pilot committed an error activating the 7500 squawking signal," the statement said, referring to the hijack alarm.
It said an investigation would still be needed to confirm why the distress signal was pressed.
"Appropriate penalties and sanctions will be imposed on the erring pilot if the result is indeed a human error," it said.
There were 410 passengers on board, plus four pilots and 17 crew members, airport general manager Ed Monreal told reporters.
Many of them were returning from the annual Islamic pilgrimage in Saudi Arabia.
One of the passengers, Aida Majud, said they were not told why they were being kept on the plane.
"When we saw the armed men we thought, what's the problem. We wanted to know what was happening," Majud told ABS-CBN television network.
But she said the atmosphere was calm, with some speculating President Rodrigo Duterte had come to the airport to welcome back the pilgrims and that the armed men surrounding the plane were his security personnel.
Majud said passengers had to undergo body checks after getting off the plane to ensure no one was carrying weapons.
Airport officials said there were no major disruptions to aviation traffic, with planes continuing to land and take off, because the Saudia aircraft had been kept at an isolated area.
The carrier is known as Saudia.