U.S. and Japanese authorities have ordered airlines to stop flying their Boeing 787s until they can show they've fixed a fire risk linked to battery failures aboard the closely watched Dreamliners.

The moves by the U.S. Federal Aviation Administration and the Japanese government follow an emergency landing in Japan that prompted that country's two major airlines to ground their fleets of 787s, and a similar problem aboard a Dreamliner on the ground in Boston nine days earlier.

"The battery failures resulted in release of flammable electrolytes, heat damage, and smoke on two Model 787 airplanes," the FAA announced Wednesday evening. "The root cause of these failures is currently under investigation. These conditions, if not corrected, could result in damage to critical systems and structures, and the potential for fire in the electrical compartment."

The only U.S. carrier to operate the eagerly awaited, long-delayed jetliner is United Airlines, which said earlier Wednesday that it had inspected its fleet of six 787s and would continue flying them. United spokeswoman Christen David said Wednesday evening that the airline would comply with the order "and will work closely with the FAA and Boeing on the technical review."

The FAA noted that its directive also signals international aviation authorities to take "parallel action" regarding their own airlines.

The first commercial Dreamliner flight took off in October 2011, flying from Tokyo to Hong Kong, and the planes flew without major problems for more than a year.

Since July, the growing list of reported troubles aboard the planes include a fuel leak, an oil leak, two cracked engines, a damaged cockpit window and a battery problem. The FAA announced a safety review of the aircraft last week.

In the most serious incident so far, an All Nippon Airlines (ANA) 787 with 129 people aboard made an emergency landing after a battery alarm Wednesday morning. Those on board reported a burning smell in the cabin, and an alarm indicated smoke in a forward electrical compartment.

Hours later, ANA and Japan Airlines announced that they were grounding their Dreamliners pending an investigation.

And on Thursday, the Japanese government ordered that all 787s be kept out of service until battery safety could be assured.