14:13, 09.Nov 2018
Singapore and Australia's aviation authorities have temporarily banned Boeing 737 Max aircraft from flying into and out of their countries.
The decision comes after an Ethiopian Airlines Boeing Max 8 crashed on Sunday, killing 157 people on board.
It was the second fatal accident involving that model in less than five months.
Singapore's Changi Airport is the world's sixth busiest and a major hub connecting Asia to Europe and the US.
But only a handful of airlines operate Max aircraft in and out of the country.
No Australian airlines operate the Boeing 737 Max, and only two foreign airlines - SilkAir and Fiji Airways - fly the model into the country.
Shane Carmody, who is in charge of aviation safety at Australia's Civil Aviation Safety Authority, said the suspension would remain in place while the organisation awaited "for more information to review the safety risks".
Several airlines and regulators around the world have already grounded the Max 8 model following the crash.
South Korea has asked Eastar Jet, the only airline in the country to own Max 8s, to ground its planes from Wednesday, according to the AFP news agency.
Is disruption likely?
Singapore's aviation authority said the affected airlines include SilkAir, which operates six Boeing 737 Max 8 aircraft, as well as China Southern Airlines, Garuda Indonesia, Shandong Airlines and Thai Lion Air.
It said it is working with airlines and Changi Airport to minimise the impact on passengers. Experts told the BBC that disruption was likely, however.
Aviation consultant Ian Thomas said: "This is sure to lead to significant flight cancellations and disruption to schedules as the airlines involved switch to other aircraft types (assuming they are available)."
The BBC's Karishma Vaswani, who is at Changi Airport, reports orderly scenes. Some flights have been cancelled but it is not known if the suspension is to blame.
In the US, the country's Federal Aviation Administration (FAA) told airlines on Monday it believes Boeing's 737 Max 8 model to be airworthy, despite the two fatal crashes.
What is a Boeing 737 Max aircraft?
The Boeing 737 Max fleet of aircraft are the latest in the company's successful 737 line. The group includes the Max 7, 8, 9 and 10 models.
By the end of January, Boeing had delivered 350 of the Max 8 model out of 5,011 orders. A small number of Max 9s are also operating.
The Max 7 and 10 models, not yet delivered, are due for roll-out in the next few years.
The Max 8 that crashed on Sunday was one of 30 ordered as part of Ethiopian Airlines' expansion. It underwent a "rigorous first check maintenance" on 4 February, the airline said.