A Nairobi-bound Ethiopian Airlines Boeing crashed minutes after take-off from Addis Ababa on Sunday, killing all eight crew and 149 passengers on board, including tourists, business travellers, and “at least a dozen” UN staff.

Ethiopia declared a national day of mourning for Monday amid a global stream of condolences for loved ones, many of whom gathered in tears at Nairobi's Jomo Kenyatta International Airport (JKIA).

“The House of People's Representatives have declared March 11, 2019, a national day of mourning for citizens of all countries that have passed in this tragic accident,” Prime Minister Abiy Ahmed's office said on Twitter.

Identities of the victims from 35 countries started to emerge as foreign governments and the United Nations reacted with shock.

“Deeply saddened by the news this morning of the plane crash in Ethiopia, claiming the lives of all on board. My heartfelt condolences to the families and loved ones of all the victims - including our own @UN staff - who perished in this tragedy,” tweeted UN Secretary-General Antonio Guterres.

The passengers included “at least a dozen” UN-affiliated staff headed for an annual assembly of the UN Environment Programme, which opens in Nairobi on Monday with some 4,700 heads of state, ministers, business leaders, senior UN officials and civil society representatives, a UN source told AFP.

Some of the UN staff were from the World Food Programme and UN refugee agency (UNHCR), the agencies said.

Wife, son, daughter dead

Slovak MP Anton Hrnko was among the bereaved.

“It is with deep sorrow that I announce that my dear wife, Blanka, son Martin and daughter Michala, died in the air disaster in Addis Ababa this morning,” he wrote on Facebook.

Flight ET 302 ploughed into a field 60 kilometres southeast of Addis Ababa on what the airline's CEO Tewolde GebreMariam labelled a “very sad and tragic day”.

An eyewitness told AFP the plane came down in flames.

“The plane was already on fire when it crashed to the ground. The crash caused a big explosion,” Tegegn Dechasa recounted at the site, littered with passenger belongings, human remains, and airplane parts around a massive crater at the point of impact.

“The plane was in flames in its rear side shortly before the crash. The plane was swerving erratically before the crash.”

The Boeing 737-800MAX was brand new, delivered to state-owned Ethiopian Airways on November 15, said the carrier, Africa's largest.

The plane is the same type as the Indonesian Lion Air jet that crashed in October, 13 minutes after take-off from Jakarta, killing all 189 people on board.

'Devastating'

Ethiopian Airlines said the plane had taken off at 8:38am (0538 GMT) from Bole International Airport and “lost contact” six minutes later. It came down near Tulu Fara village outside the town of Bishoftu.

The carrier, which changed its logo on Twitter to black and white from its trademark green, yellow, and red, said “there are no survivors”.

“We can only hope that she is not on that flight,” Peter Kimani, who had come to fetch his sister at Nairobi's JKIA, told AFP after news of the disaster reached those waiting in the arrivals hall.

Loved ones were later brought to the onsite Sheraton Hotel where they were debriefed and offered counselling. Journalists were not allowed in, but could hear sobbing from inside.

Ethiopian Airlines said Kenya had the largest number of casualties with 32, followed by Canada with 18, Ethiopia nine, then Italy, China, and the United States with eight each.

Britain and France each had seven people on board, Egypt six, and Germany five, according to the airline. France's government later said there were eight French victims though there was no explanation for the discrepency.

Twelve countries in Africa and 14 in Europe had citizens among the victims.

African Union commission chief Moussa Faki Mahamat spoke of “utter shock and immense sadness”, while Mahboub Maalim, executive secretary of the IGAD East African bloc, said the region and the world were in mourning.

Prime Minister Justin Trudeau of Canada and his British counterpart Theresa May both described the news as “devastating”.

Foreign Office Spokesperson Dr Mohammad Faisal took to Twitter to share condolences on behalf of the government and people of Pakistan.

Sympathy messages also came from the governments of Ethiopia, Kenya, Uganda, Britain, Germany, France and the US.

Pilot had 'difficulties'

GebreMariam said the plane had flown in from Johannesburg earlier Sunday, spent three hours in Addis and was “despatched with no remark”, meaning no problems were flagged.

Asked if the pilot had made a distress call, the CEO said “the pilot mentioned that he had difficulties and he wants to return. He was given clearance” to turn around.

Ethiopian and American investigators will probe the crash, said GebreMariam.

For one family member in Nairobi, there was a happy ending.

Khalid Ali Abdulrahman was waiting for his son who works in Dubai and feared the worst when a security official told him the plane had crashed.

“I was shocked, but shortly after, my son contacted me and told me he is still in Addis and did not board that flight. He is waiting for the second one which has been delayed.”

For its part, the plane's maker, US giant Boeing, said it was "aware" of the accident "and is closely monitoring the situation".