The US are issuing "emergency order" and grounding all Boeing 737 Max 8 and Max 9 aircrafts, following the Ethiopia crash, Donald Trump has confirmed.
President Trump said any planes which are currently in the air will go its destination and thereafter be grounded until further notice.
He said: "Our hearts go out to all those who lost loved ones, to their friends and family... it's a terrible, terrible thing.
"Boeing is an incredible company, they are working very, very hard right now and hopefully they'll very quickly come up with the answer but until they do, plans will remain grounded," he added.
Canada also grounded the Boeing 737 Max 8 aircraft earlier and three domestic airlines operating more than 40 Max 8 jets would not be able to operate in Canadian airspace from Wednesday.
The US Federal Aviation Administration backed the jet's airworthiness but said it was reviewing all available data.
"Thus far, our review shows no systemic performance issues and provides no basis to order grounding the aircraft," acting FAA administrator Daniel K Elwell said in a statement.
"Nor have other civil aviation authorities provided data to us that would warrant action."
The European Union Aviation Safety Agency issued orders for the aircraft to be grounded from 7pm on Tuesday. It means planes flying over, or into, Europe will not be able to complete their journeys.
In a statement it said it had issued the directive "as a precautionary measure", adding it is "taking every step necessary to ensure the safety of passengers".
It extended the ban to include MAX 8 and MAX 9, although only the first type was involved in the crash in Ethiopia.
The move unifies a series of nationwide bans across Europe.
France, Germany, the Netherlands, Ireland and the UK all banned the planes from their airspace on Tuesday afternoon.
Internationally, authorities in Egypt, Thailand, Hong Kong, Kosovo and Lebanon on Wednesday joined Australia, South Korea, Singapore, China and Indonesia and others in grounding the aircraft.
A ban announced by the UK's Civil Aviation Authority led to confusion for passengers and airlines on Tuesday.
Shortly after the CAA announcement, a Turkish Airlines flight from London's Gatwick Airport departed for Istanbul using the banned aircraft.
A second flight, operated by TUI, was crossing the English Channel. It landed safely at Manchester Airport.
The CAA's decision to ban Boeing's 737 Max covered "any commercial passenger flights from any operator arriving, departing or overflying UK airspace" and remained in place on Wednesday.
Two further Turkish Airways planes were turned away from British airspace whilst flying over central Europe on Tuesday. It is believed the aircraft were due to land at London Gatwick and Birmingham airport later that afternoon.
Across Europe, all 737 Max 8 aircraft operated by Turkish Airlines returned to their origin, inbound flights to Istanbul continued.
Norwegian said it was cancelling all its flight using the Boeing 737 Max 8 aircraft as a safety measure.
Sara Tor, a passenger on-board one of the Turkish Airlines flights from Istanbul has told ITV News how passengers were initially told the plane was returning to Turkey as UK airspace was closed. They were then told it was due to the weather.
It was only after returning to Istanbul she discovered the aircraft she was travelling on was the same model as the one involved in both the Ethiopian crash and a previous Lion Air disaster.
The diversions and cancellations bring questions over the aircraft's safety record into the spotlight, with Boeing shares falling seven per cent on Tueday, and the aviation world taking stock of the latest disaster to hit it.
Meanwhile, the black box from the doomed jet that crashed and killed all 157 people on board will be sent overseas for analysis, an Ethiopian Airlines spokesman has said.
"What we can say is we don't have the capability to probe it here in Ethiopia," a spokesman said.
ITV News Correspondent Neil Connery explains how the investigation is unfolding in Ethiopia
Boeing earlier said it was “working closely” with the Federal Aviation Administration (FAA) “on development, planning and certification” of a software enhancement, due to be rolled out in the coming weeks.
Boeing said it had been developing a flight control software enhancement for several months after the Lion Air Flight 610 disaster last year.
Outside of Europe, the following countries have grounded the Boeing model:
A Lion Air model of the same plane crashed in Indonesia in October.
While defending the Max as safe, Boeing is promising to upgrade some flight-control software "in the coming weeks".
Boeing began working on the changes shortly after the Lion Air crash. It is tweaking a system designed to prevent an aerodynamic stall if sensors detect that the plane's nose is pointed too high and its speed is too slow.
Officials at Lion Air in Indonesia said sensors on their plane produced erroneous information on its last four flights, triggering an automatic nose-down command which the pilots were unable to overcome. The plane plunged into the sea.
A Boeing spokesman said once updated software is installed, the system will rely on data from more than one sensor to trigger a nose-down command.
Also, the system won't repeatedly push the nose down, and it will reduce the magnitude of the change, he said. There will also be more training for pilots.