The Federal Aviation Administration has grounded six new Boeing 787 Dreamliners being flown by United Airlines after a spate of incidents raised doubts about the safety of the revolutionary high-tech plane.

The action late Wednesday came over concern about the plane’s lithium batteries, which overheated in two 787s in the past week. The most recent incident came Wednesday, when alarms went off and the pilots smelled a burning battery on a domestic All Nippon Airways bound for Tokyo.

Early Thursday, the European Aviation Safety Agency said it was endorsing the FAA’s action until the risk of battery fires and other safety concerns are resolved, according to the Associated Press. The Polish airline LOT is the only European carrier currently flying the jetliner.

ANA and Japan Airlines, which fly 24 of the 50 Dreamliners in service, grounded their 787s after the plane made an emergency landing. The FAA ordered United’s fleet of six planes to cease flying later Wednesday. United is the only U.S. carrier flying 787s.

Boeing, which last week defended the problems with the new plane as “teething pains,” had no immediate comment on the groundings.

FAA Administrator Michael P. Huerta and U.S. Transportation Secretary Ray LaHood, who appeared with Boeing President Ray Conner on Friday to defend the safety of the new plane, did not comment on the grounding order.

In a statement, the FAA said it would work with Boeing and the airlines flying 787s — which include carriers in India, Poland, Qatar, Ethiopia and Chile — to return the planes to service quickly.

The FAA said it had alerted aviation authorities in the foreign carriers’ home nations of the grounding order.

The National Transportation Safety Board also dispatched an investigator to work with Japanese officials examining the plane that made Wednesday’s emergency landing.

“Initial reports indicate that the crew received multiple messages in the cockpit concerning the battery and other systems that were affected, and also reported smoke in the cockpit and an odor in the cabin,” the NTSB said in a statement. “The airplane subsequently landed, and passengers and crew evacuated via emergency slides.”

The incident Wednesday came after a Jan. 7 fire aboard an empty Japan Airlines plane parked at Boston’s Logan International Airport. There also was a fuel leak on another of the airline’s 787s as it prepared for takeoff at Logan last week and brake problems that caused cancellation of an ANA flight in Japan.

The FAA said the two battery failures resulted in the release of flammable electrolytes, heat damage and smoke.

“These conditions, if not corrected, could result in damage to critical systems and structures and the potential for fire in the electrical compartment,” the FAA said.

The 787, known as the Dreamliner, is the first in a new generation of lighter, more fuel-efficient carbon-fiber airplanes in which electronics have replaced hydraulic control systems.

The planes are priced between $207 million and $243 million, and Boeing says more than 800 of them are on order. Boeing is the world’s largest aerospace company and a top U.S. exporter.

In defending the safety of the plane Friday, Conner and the two federal officials said it underwent 200,000 hours of testing before winning FAA approval. Conner said the concerns raised about the 787 were comparable to those that surfaced when Boeing introduced the 777 in the 1990s.

Boeing shares fell $2.60, or 3.4 percent, to close at $74.34 Wednesday. Its stock continued to fall in after-hours trading, 1.9 percent to $72.90.