Pressure on Boeing Co. escalated after China and Indonesia decided to ground flights of the U.S. planemaker’s newest 737 jet in response to the second deadly crash of the best-selling narrow-body in five months.

Boeing shares fell sharply in early U.S. trading, a day after Ethiopian Airlines Flight 302 crashed and killed all 157 people on board. Africa’s biggest carrier also decided not to use its 737 Max 8 planes until further notice. China ordered its carriers to ground all 96 of the aircraft, while Indonesia’s air safety regulator said it will halt flights involving the Boeing planes starting Tuesday.

For Boeing, the latest disaster soon drew comparisons to a Lion Air crash in Indonesia that killed 189 people, pushing the Chicago-based planemaker a step closer to a crisis. A blanket grounding of the 737 Max, which generates almost one-third of the company’s operating profit, in China also raised the specter of other countries following suit. While Indonesia’s air safety regulator also ordered local airlines keep the 737 on the ground, South Korea began a special inspection of the aircraft.

“The B737 Max design is dangerously flawed,” said Mohan Ranganathan, a former commercial pilot and an aviation safety consultant based in the southern India city of Chennai. “There is a definite similarity between Lion Air and Ethiopian Airlines Max crashes.”

In Europe, regulators said they’re in contact with their U.S. counterparts as well as Boeing, but that it’s too soon to take action.

Shares of Boeing sank 9.6 percent to $382.11 in early U.S. trading. Safran SA, which makes engines for the Max in the CFM International venture with General Electric Co., was down 1.8 percent as of 11:15 a.m. in Paris.

Chinese airlines accounted for about 20 percent of 737 Max deliveries worldwide through January, according to Boeing’s website, and further purchases of the Chicago-based planemaker’s aircraft are said to have been touted as a possible component of a trade deal with the U.S.

China Southern Airlines Co. has 16 of the aircraft, with another 34 on order, according to data through January on Boeing’s website. China Eastern Airlines Corp. has 13, while Air China Ltd. has 14, Boeing says. Other Chinese airlines that have bought the Max include Hainan Airlines Holdings Co. and Shandong Airlines Co., the data show.

The single-aisle 737 Max is poised to generate about $30 billion in annual revenue as factory output rises to a 57-jet monthly pace this year, according to Bloomberg Intelligence estimates.

The disaster in Ethiopia followed the crash of Lion Air’s 737 Max off the coast of Indonesia on Oct. 29. A preliminary report into that disaster indicated that pilots struggled to maintain control following an equipment malfunction.

The doomed Ethiopian jetliner left Addis Ababa at 8:38 a.m. local time, and contact was lost six minutes later, the company said in a statement. There were people from 35 nations on board, including 32 Kenyans, 18 Canadians, nine Ethiopians and eight Americans. The United Nations, which is hosting an environmental conference this week in Nairobi, said it lost 19 staff members in the crash.

The pilot of the ET302 reported problems shortly after takeoff and was cleared to return to the airport, said the airline’s chief executive officer, Tewolde GebreMariam. The 737 Max 8 hadn’t had any apparent mechanical issues on an earlier flight from Johannesburg, he said.

Ethiopian Airlines had five of the planes in operation as of the end of January and orders for a further 25, according to Boeing’s website.

Indonesia’s transportation safety committee said Monday it offered to help with the Ethiopian Airlines crash investigation and will discuss the possibility of grounding Boeing 737 Max jets operated by the nation’s airlines. Jet Airways India Ltd. and SpiceJet Ltd., two Indian airlines that use the 737 Max jet, and the country’s regulators have asked Boeing for information following the Ethiopia crash.

Southwest Airlines Says it’s “confident in the safety of our fleet” including its 34 737 Max 8 planes American Airlines Will closely monitor the investigation via Boeing and NTSB Singapore Airlines Monitoring the situation; the 737 Max 8 flights operated by SilkAir are flying as scheduled Icelandair Says it’s had no issues with its three 737 Max 8s Korean Air Due to receive its first Max in April, is monitoring the situation Cayman Airways Grounds both its Boeing 737 Max 8 aircraft Thailand Says it currently has no plans to ground Boeing 737 Max jets China Grounds entire fleet of Boeing 737 Max 8 jets. China Eastern to talk with Boeing about losses caused by grounding. Flydubai Says it’s monitoring situation and in touch with BoeingBoeing said earlier that it was preparing to send a technical team to assist the investigation into the Ethiopian Airlines plane, which was delivered new in November to Africa’s biggest carrier.

Boeing also said it is postponing the “external debut” of its 777X model and related media events scheduled for this week because of the accident. There is no change to the plane’s schedule or progress, Boeing said.

In South Korea, authorities have been working with Eastar Jet Co. to ensure the safety of the two 737 Max 8 planes the budget carrier operates, a spokesman for Eastar said Monday. The company is currently the only airline in the country that flies the aircraft and plans to add four more to its fleet this year.

The U.S. Federal Aviation Administration, which originally certified the 737 Max, declined to add to its earlier statement saying it is “closely monitoring developments” in the Ethiopian investigation.

A U.S.-ordered grounding of an entire model of aircraft is extremely rare and in the past has typically not occurred so soon during an investigation when few details are known.

The last time the agency did so was in January 2013 as a result of overheating lithium-ion batteries on Boeing’s 787 model. The agency only acted after the second such incident occurred.