ADDIS ABABA, Ethiopia (AP) - An Ethiopian Airlines jet faltered and crashed Sunday shortly after takeoff, carving a gash in the earth and spreading global grief to 35 countries that had someone among the 157 people who were killed.

There was no immediate indication why the plane went down in clear weather while on a flight to Nairobi, the capital of neighboring Kenya. The crash was strikingly similar to that of a Lion Air jet in Indonesian seas last year, killing 189 people. Both accidents involved the Boeing 737 Max 8, and China ordered a temporarily grounding of those planes for Chinese airlines Monday.

The crash shattered more than two years of relative calm in African skies, where travel had long been chaotic. It also was a serious blow to state-owned Ethiopian Airlines, which has expanded to become the continent's largest and best-managed carrier and turned Addis Ababa into the gateway to Africa.

"Ethiopian Airlines is one of the safest airlines in the world. At this stage we cannot rule out anything," CEO Tewolde Gebremariam told reporters. He visited the crash site, standing in the gaping crater flecked with debris.

Black body bags were spread out nearby while Red Cross and other workers looked for remains. As the sun set, the airline's chief operating officer said the plane's flight data recorder had not yet been found.

Around the world, families were gripped by grief. At the Addis Ababa airport, a woman called a mobile number in vain. "Where are you, my son?" she said, in tears. Others cried as they approached the terminal.

Henom Esayas, whose sister's Nigerian husband was killed, told The Associated Press they were startled when a stranger picked up their frantic calls to his mobile phone, told them he had found it in the debris and promptly switched it off.

Shocked leaders of the United Nations, the U.N. refugee agency and the World Food Program announced that colleagues had been on the plane. The U.N. migration agency estimated some 19 U.N.-affiliated employees were killed. Both Addis Ababa and Nairobi are major hubs for humanitarian workers, and many people were on their way to a large U.N. environmental conference set to begin Monday in Nairobi.

The Addis Ababa-Nairobi route links East Africa's two largest economic powers. Sunburned travelers and tour groups crowd the Addis Ababa airport's waiting areas, along with businessmen from China, Gulf nations and elsewhere.

A list of the dead released by Ethiopian Airlines included passengers from China, the United States, Saudi Arabia, Nepal, Israel, India and Somalia. Kenya lost 32 citizens. Canada, 18. Several countries including the United States lost four or more people.

Ethiopian officials declared Monday a day of mourning.

At the Nairobi airport, hopes quickly dimmed for loved ones. "I just pray that he is safe or he was not on it," said Agnes Muilu, who had come to pick up her brother.

The crash is likely to renew questions about the 737 Max , the newest version of Boeing's popular single-aisle airliner, which was first introduced in 1967 and has become the world's most common passenger jet.

China's civil aviation authority on Monday ordered a nine-hour grounding of that model plane for safety reasons and said it would consult with Boeing and others further.

Indonesian investigators have not determined a cause for the October crash, but days after the accident Boeing sent a notice to airlines that faulty information from a sensor could cause the plane to automatically point the nose down.

The Lion Air cockpit data recorder showed that the jet's airspeed indicator had malfunctioned on its last four flights, though the airline initially said problems had been fixed.

Safety experts cautioned against drawing too many comparisons between the two crashes until more is known about Sunday's disaster.

The Ethiopian Airlines CEO "stated there were no defects prior to the flight, so it is hard to see any parallels with the Lion Air crash yet," said Harro Ranter, founder of the Aviation Safety Network, which compiles information about accidents worldwide.

The Ethiopian plane was new, delivered to the airline in November. The Boeing 737 Max 8 was one of 30 meant for the airline, Boeing said in July. The jet's last maintenance was on Feb. 4, and it had flown just 1,200 hours.

The plane crashed six minutes after departure , plowing into the ground at Hejere near Bishoftu, or Debre Zeit, some 50 kilometers (31 miles) outside Addis Ababa, at 8:44 a.m.

The jet showed unstable vertical speed after takeoff, air traffic monitor Flightradar 24 said. The senior Ethiopian pilot, who joined the airline in 2010, sent out a distress call and was given clearance to return to the airport, the airline's CEO told reporters.

In the U.S., the Federal Aviation Administration said it would join the National Transportation Safety Board in assisting Ethiopian authorities with the crash investigation. Boeing planned to send a technical team to Ethiopia.

The last deadly crash of an Ethiopian Airlines passenger flight was in 2010, when a plane went down minutes after takeoff from Beirut, killing all 90 people on board.

African air travel has improved in recent years, with the International Air Transport Association in November noting "two years free of any fatalities on any aircraft type."

Sunday's crash comes as the country's reformist young prime minister, Abiy Ahmed, has vowed to open up the airline and other sectors to foreign investment in a major transformation of the state-centered economy.

Speaking at the inauguration in January of a new passenger terminal in Addis Ababa to triple capacity, the prime minister challenged the airline to build a new "Airport City" terminal in Bishoftu - where Sunday's crash occurred.