U.S. aviation regulators reiterated that they see no safety issue with the beleaguered Boeing Co. 737 Max jetliner that warrants grounding the plane despite a pair of deadly crashes and the move by more than 40 other nations to temporarily take it out of service.

Federal Aviation Administration acting chief Daniel Elwell said Tuesday evening that the agency continues to closely monitor an investigation into a fatal crash of one of the planes on Sunday in Ethiopia and will take action if necessary.

“Thus far, our review shows no systemic performance issues and provides no basis to order grounding the aircraft,” Elwell said in the statement. “Nor have other civil aviation authorities provided data to us that would warrant action.”

The statement came at the end of a whirlwind day that saw Boeing stock plummet as nation after nation moved to ground the plane despite reassurances from the agency and the Chicago-based planemaker. In addition to China and India, the influential European Aviation Safety Agency moved to ban flights of the 737 Max, Boeing’s best-selling model.

“The accident investigation is currently ongoing, and it is too early to draw any conclusions as to the cause of the accident,” EASA said in an emailed statement. The agency, which usually goes along with the FAA, said it was acting out of an abundance of caution and out of concern for passenger safety.

After President Donald Trump criticized modern airplanes for being too complicated, he spoke on the phone to Boeing Chief Executive Officer Dennis Muilenburg, two people familiar with the matter said. Muilenburg assured Trump he is confident the plane is safe, according to one of the people, who asked not to be identified discussing a private conversation.

The FAA and the U.S. National Transportation Safety Board have teams observing Ethiopian authorities on their investigation of Sunday’s crash. All 157 people aboard the Ethiopian Airlines 737 Max 8 died when it plunged into the ground at high speed about six minutes after takeoff Sunday morning near Addis Ababa. Investigators have released no information about what caused the crash.

“In the course of our urgent review of data on the Ethiopian Airlines Flight 302 crash, if any issues affecting the continued airworthiness of the aircraft are identified, the FAA will take immediate and appropriate action,” Elwell said.

The Ethiopian crash was the second fatal accident involving the Max model within five months. A Lion Air Max 8 crashed on Oct. 29 off the coast of Indonesia, also shortly after takeoff, following a malfunction of a software feature on the plane repeatedly forced it into a dive, according to that country’s investigation. All 189 people aboard died.

While the Ethiopian plane descended unexpectedly twice after takeoff, similar to the repeated dips made by the Lion Air plane, there has not been any evidence released that directly links the two crashes.

Boeing reiterated earlier Tuesday that it has “full confidence” in the safety of the 737 Max. Since the FAA isn’t mandating any new action, “based on the information currently available, we do not have any basis to issue new guidance to operators.”

The single-aisle Max family is Boeing’s largest seller and accounts for almost one-third of the company’s operating profit. The company’s stock fell 6.1 percent to $375.41 at the close in New York, bringing the two-day drop to 11 percent. The company has lost almost $27 billion in market value this week.

As a result of the Lion Air investigation, the FAA on Monday said it planned to order Boeing to make software fixes to the plane’s Maneuvering Characteristics Augmentation System by April.

MCAS automatically pushes the Max jet’s nose down in limited situations to keep air flowing over the wings to prevent a dangerous aerodynamic stall. Because a faulty sensor on the Lion Air plane was sending it erroneous data, it attempted to repeatedly dive, forcing the pilots to pull the plane back up. The aircraft crashed when pilots failed to arrest the last dive.

Boeing plans to make several changes to the system, it announced. It will limit the number of times MCAS can repeatedly push down the nose if pilots counteract it and make it less powerful so pilots can overcome the motion more easily. It will also add redundancy to the sensors to make the malfunction that occurred in Lion Air less likely.