US plane maker Boeing is under tough scrutiny after an Ethiopian Airlines 737 crash on Sunday killed all 157 people on board.
It was the second crash in five months involving a 737 Max 8, and comparisons are being drawn with a Lion Air accident in Indonesia last October.
In response, a number of airlines have now grounded all planes of the same model.
However, experts warn it is too early to say what caused the latest disaster.
Ethiopian Airlines says the plane, flight ET302, crashed at 08:44 local time (05:44 GMT), just six minutes after it left Addis Ababa. The aircraft, bound for Nairobi, came down near the town of Bishoftu, 60km (37 miles) south-east of the capital.
The pilot had reported difficulties and had asked to return to Addis Ababa, the airline said.
“At this stage, we cannot rule out anything,” Ethiopian Airlines CEO Tewolde Gebremariam told reporters at Bole International Airport in the capital.
Visibility was said to be good but air traffic monitor Flightradar24 reported that the plane’s “vertical speed was unstable after take-off”.
The pilot was named as Senior Captain Yared Getachew who had a “commendable performance” with more than 8,000 hours in the air, the airline said.
The plane that crashed was among six of 30 that Ethiopian Airlines had ordered as part of its expansion. It underwent a “rigorous first check maintenance” on 4 February, the airline tweeted.