HEJERE, Ethiopia -- Airlines in Ethiopia, China, Indonesia and elsewhere grounded the Boeing 737 Max 8 jetliner Monday after the second devastating crash of one of the planes in five months. But Boeing said it had no reason to pull the popular aircraft from the skies.

As the East African country mourned the 157 victims of the Ethiopian Airlines plane that went down in clear weather shortly after takeoff Sunday, investigators found the jetliner's two flight recorders at the crash site outside the capital of Addis Ababa.

An airline official, however, said one of the recorders was partially damaged and "we will see what we can retrieve from it." The official spoke on condition of anonymity for lack of authorization to speak to the media.

A witness to the crash told The Associated Press smoke was coming from the rear of the plane before it hit the ground.

"Before falling down, the plane rotated two times in the air, and it had some smoke coming from the back then, it hit the ground and exploded," Tamrat Abera said. "When the villagers and I arrived at the site, there was nothing except some burning and flesh."

Ethiopian authorities are leading the investigation into the crash, assisted by the U.S., Kenya and others.

The crash was similar to that of a Lion Air jet of the same model crashing in Indonesian seas last year, killing 189 people. The crash was likely to renew questions about the 737 Max 8, the newest version of Boeing's single-aisle airliner, which was first introduced in 1967 and has become the world's most common passenger jet.

Safety experts cautioned against drawing too many comparisons between the two crashes until more is known. Besides the groundings by airlines in Ethiopia, China and Indonesia, Caribbean carrier Cayman Airways, Comair in South Africa and Royal Air Maroc in Morocco temporarily grounded their Max 8s.

Ethiopian Airlines decided to ground its remaining four 737 Max 8s until further notice as "an extra safety precaution," spokesman Asrat Begashaw said. The carrier had been using five of the planes and awaiting delivery of 25 more.

But Chicago-based Boeing said it did not intend to issue any new recommendations about the aircraft to its customers. It plans to send a technical team to the crash site to help investigators and issued a statement saying it was "deeply saddened to learn of the passing of the passengers and crew" on the jetliner.

Among the airlines still using the plane are Southwest, American and Air Canada.

In Washington, Transportation Secretary Elaine L. Chao said passenger safety was the first priority for the administration.

"I want travelers to be assured and that we are taking this seriously and monitoring latest developments," she said.

It's unusual for authorities to take the step of grounding planes, and it's up to each country to set standards on which planes can fly and how those planes are maintained, said Todd Curtis, an aviation safety analyst who directs the Airsafe.com Foundation.

"If there is a suspicion ... that there's not only something inherently wrong with 737 Max 8 aircraft, but there are no procedures in place to cure the problem, then yes, they should either ground the plane, or there are several levels of things they could do," Curtis said.

People from 35 countries died in the crash six minutes after takeoff from Ethiopia's capital for Nairobi.