BEIJING (AP) -- China's civilian aviation authority ordered all Chinese airlines to ground their Boeing 737 Max 8 planes indefinitely on Monday after one of the aircraft crashed in Ethiopia.
The crash of the Ethiopian Airlines jet shortly after it took off from Addis Ababa is drawing renewed scrutiny of the plane just four months after a crash of the same model of aircraft in Indonesia.
Meanwhile, a spokesman for Ethiopian Airlines, Asrat Begashaw, said the carrier had grounded its remaining four 737 Max 8 planes until further notice as an "extra safety precaution."
The airline was using five new 737 Max 8s and awaiting delivery of 25 more. Begashaw said the search for body parts and debris from the crash was continuing.
China's Civil Aviation Administration said that it ordered airlines to ground all 737 Max 8 aircraft as of 6 p.m. (1000 GMT) Monday, in line with the principle of "zero tolerance for security risks."
It said it would issue further notices after consulting with the U.S. Federal Aviation Administration and Boeing.
China Southern Airlines is one of Boeing's biggest customers for the aircraft.
Cayman Airways also said it was temporarily grounding the two Boeing 737 Max 8 aircraft it operates, as of Monday.
Real time flight radar apps showed dozens of the aircraft still operating around the globe.
Chicago-based Boeing said it would send a technical team to the crash site to help Ethiopian and U.S. investigators. It issued a statement saying it was "deeply saddened to learn of the passing of the passengers and crew" on the Ethiopian Airlines Max airplane.
The 737 is the best-selling airliner in history, and the Max, the newest version of it with more fuel-efficient engines, is a central part of Boeing's strategy to compete with European rival Airbus.
Boeing said it did not intend to issue any new guidance to its customers.
"Safety is our number one priority and we are taking every measure to fully understand all aspects of this accident, working closely with the investigating team and all regulatory authorities involved," Boeing said in a statement.
The head of Indonesia's national transport safety agency, Soerjanto Thahjono, offered to aid the Ethiopian investigation into Sunday's crash.
Like the Ethiopian Airlines crash, which happened minutes after the jet's takeoff from Addis Ababa and killed all 157 people on board, the Lion Air jet that crashed on Oct. 29 off Indonesia had erratic speed during the few minutes it was in the air.
The latest crash is bringing renewed scrutiny since the plane was new and the weather was clear. Its pilots had tried to return to the airport.
Safety experts cautioned, however, against drawing too many parallels between the two crashes.
"I do hope though that people will wait for the first results of the investigation instead of jumping to conclusions based on the very little facts that we know so far," said Harro Ranter, founder of the Aviation Safety Network, which compiles information about accidents worldwide.
The situation will be better understood after investigators find and analyze the Ethiopian plane's black boxes, said William Waldock, an aviation-safety professor at Embry-Riddle Aeronautical University.
He said the way the planes both crashed -- a fatal nosedive -- was likely to raise suspicion.
"Investigators are not big believers in coincidence," he said.
Waldock said Boeing will look more closely at the flight-management system and automation on the Max.
Boeing has delivered about 350 737 Max planes to many airlines and has orders for more than 5,000.
Alan Diehl, a former National Transportation Safety Board investigator, said in both crashes the pilots ran into problems shortly after takeoff. Reports of large variations in vertical speed during the Ethiopian jetliner's ascent were "clearly suggesting a potential controllability problem."
Other possible causes include engine problems, pilot error, weight load, sabotage or bird strikes, he said.
Ethiopian has a good reputation and the company's CEO told reporters no problems were spotted before Sunday's fight, but investigators also will look into the plane's maintenance, which may have been an issue in the Lion Air crash.
The NTSB said it was sending a team of four to assist Ethiopian authorities. Boeing and the U.S. investigative agency are also involved in the Lion Air probe.
Days after the Oct. 29 accident, Boeing sent a notice to airlines that faulty information from a sensor could cause the plane to automatically point the nose down. The automated system kicks in if sensors indicate that a plane is about to lose lift, or go into an aerodynamic stall. Gaining speed by diving can prevent a stall.
The notice reminded pilots of the procedure for handling such a situation, which is to disable the system causing the automatic nose-down movements.
Boeing Chairman and CEO Dennis Muilenburg said in December that the Max is a safe plane.
Indonesian investigators are examining whether faulty readings from a sensor might have triggered the automatic nose-down command to the plane, which the Lion Air pilots fought unsuccessfully to overcome.
The Lion Air plane's flight data recorder showed problems with an airspeed indicator on at least four previous flights, although the airline initially said the problem was fixed.
The Lion Air incident appears not to have harmed sales of the Max. Boeing's stock fell nearly 7 percent on the day of the Lion Air crash. Since then it has soared 26 percent higher, compared with a 4 percent gain in the Standard & Poor's 500 index.