Some 128 Boeing 777 aircraft using the same Pratt & Whitney engine which failed on a flight out of Denver have now been grounded, a spokeswoman for the giant US planemaker confirmed on Monday.
"I have just had confirmation that all the 777s equipped with this engine have been grounded," she said in a text message to AFP.
As well as United Airlines, the PW4000 engine type was also used by Japan's ANA and JAL groups, plus South Korea's Asiana Airlines.
In a statement Sunday, the company had recommended that all the aircraft concerned should be grounded as US regulators investigated a United Airlines flight which was forced to return to Denver airport after one of its engines caught fire and broke up.
A video shot from inside the aircraft -- which had 231 passengers and 10 crew onboard -- showed the right engine ablaze and wobbling on the wing of the Boeing 777-200.
Its front cowling -- which landed in the front yard of a house, missing it by inches, was entirely missing as the aircraft returned to Denver airport.
There were no injuries on the plane or on the ground, authorities said.
Earlier on Monday, Japan's transport ministry ordered Japan Airlines and All Nippon Airways to ground more than 30 aircraft equipped with Pratt and Whitney engines following the Denver incident.
The airlines had already taken the planes out of service -- 13 operated by JAL and 19 by ANA -- before the Ministry of Land, Infrastructure, Transport and Tourism issued the order Sunday.