The United States said there is "no basis" to ground Boeing 737 MAX airplanes, after a second deadly crash involving the model in less than five months prompted governments worldwide to ban the aircraft.
Despite the aviation giant's assurances that the plane is safe and reliable, the European Union, Britain and India joined China and other countries grounding the plane or banning it from their airspace as they await the results of the investigation into the crash.
But the US has so far refused to take similar action against the American aerospace giant's best-selling workhorse aircraft.
A new Ethiopian Airlines 737 MAX 8 went down minutes into a flight from Addis Ababa to Nairobi on Sunday, killing all 157 people on board. That followed the October crash of a new Lion Air jet of the same model in Indonesia, which killed 189 people shortly after takeoff from Jakarta.
The widening actions against the aircraft puts pressure on Boeing -- the world's biggest plane manufacturer -- to prove the MAX planes are safe, and the company has said it is rolling out flight software updates by April that could address issues with a faulty sensor.
There are about 350 MAX 8 planes currently in service around the world.
US President Donald Trump weighed in with a blistering tweet on Tuesday: "Airplanes are becoming far too complex to fly." "Pilot are no longer needed, but rather computer scientists from MIT," he wrote, referring to the prestigious university.
Trump later spoke by telephone to Boeing CEO Dennis Muilenburg, who assured him the aircraft is safe, an industry source told AFP.
Meanwhile, Ethiopia yesterday said it would send the black boxes of the crashed plane to Europe for analysis. The Ethiopian Airlines 737 MAX 8 was less than four months old when it went down six minutes into a flight from Addis Ababa to Nairobi on Sunday, disintegrating on impact.