The US aviation regulator says it will not ground Boeing 737 MAX planes after a crash in Ethiopia which killed 157 people, bucking a trend of countries around the world that have suspended the aircraft's operations.
The Federal Aviation Administration's acting administrator Dan Elwell said a review by the body "shows no systemic performance issues and provides no basis to order grounding the aircraft".
The European Union's aviation safety regulator on Tuesday suspended all flights in the bloc by the 737 MAX.
A US Senator who chairs a panel overseeing aviation suggested the United States take similar action following Sunday's fatal crash, the second since October involving that type of plane.
But Elwell said no foreign civil aviation authorities have provided data that would warrant action.
If any safety issues are identified during an ongoing urgent review of the Ethiopian Airlines crash, the FAA will "take immediate and appropriate action", he said.
Britain, Germany and France joined a wave of suspensions of the aircraft in the wake of the crash, and was swiftly followed by a similar decision by India, piling pressure on the United States to follow suit.
Boeing, which has seen billions of dollars wiped off its market value the crash, said it understood the countries' actions but retained "full confidence" in the 737 MAX and had safety as its priority.
The world's biggest plane maker, Boeing also said the FAA had not demanded any further action related to 737 MAX operations.
The three US airlines using the 737 MAX - Southwest Airlines Co, American Airlines Group Inc and United Airlines - stood by the aircraft.
Many potential passengers took to social media to express concerns, asking if they could change flights or cancel.
The cause of Sunday's crash, which followed another disaster with a 737 MAX five months ago in Indonesia that killed 189 people, remains unknown.
The FAA on Monday released details of a series of design changes and training requirements mandated from Boeing on the MAX fleet after the Indonesia crash.
There is no evidence yet whether the two crashes are linked. Plane experts say it is too early to speculate on the reason for the crash. Most are caused by a unique chain of human and technical factors.
In an unusual move, the European Union Aviation Safety Agency (EASA) said it was suspending all flights in the bloc of Boeing's 737 MAX 8 and 9 jets.
"Based on all available information, EASA considers that further actions may be necessary to ensure the continued airworthiness of the two affected models," it said in a statement.
However, it shied away from the even rarer step of pulling the safety certification for the plane itself, focusing instead on the softer process of restricting its use by airlines.
Flight ET 302 came down in a field soon after take-off from Addis Ababa, creating a fireball in a crater. It may take weeks or months to identify all the victims, who include a prize-winning author, a soccer official and a team of humanitarian workers.
Boeing shares fell 6.1 per cent on Tuesday bringing losses to 11.15 percent since the crash, the steepest two-day loss for the stock since July 2009. The drop has lopped $US26.65 billion off Boeing's market value.
