Search workers carry a tyre at the scene of the Ethiopian Airlines Flight ET 302 plane crash. Picture: Reuters/Tiksa Negeri

Addis Ababa - The black box recovered from the Ethiopian Airlines plane that crashed on Sunday is the cockpit voice recorder, Ethiopian state TV said on Monday.

Investigators at the crash site recovered the recorder, TV said.

The passenger jet bound for Nairobi crashed minutes after take-off, killing all 157 people on board and raising questions about the safety of the Boeing 737 MAX 8, a new model that also crashed in Indonesia in October. 

The victims came from 33 nations and included 22 United Nations' staff.

The discovery of the black box, reported by Ethiopian state TV, may shed light on the cause.

At the scene, men in Red Cross jackets picked through the dirt, putting items in black paper bags, while investigators hunted for the black box voice recorders.

"Although we don't yet know the cause of the crash, we had to decide to ground the particular fleet as extra safety precaution," Ethiopian Airlines said. 

It has four other 737 MAX 8 jets, according to flight tracking website FlightRadar24.