By Andrea Shalal-Esa

WASHINGTON (Reuters) - U.S. regulators grounded Boeing Co's 787 Dreamliner passenger jet on Wednesday, saying a recent series of safety incidents meant urgent action was needed.

The Federal Aviation Administration said it would require airlines to demonstrate that the plane's cutting-edge batteries were safe before allowing further flights. It has notified regulators in other countries of its action as well.

Japan's two leading airlines already grounded their fleets of Boeing 787s on Wednesday after one of the Dreamliner passenger jets made an emergency landing, the latest in a series of incidents that have heightened safety concerns over a plane many see as the future of commercial aviation.

All Nippon Airways Co said instruments aboard a domestic flight indicated a battery error, triggering emergency warnings. The incident was described by a transport ministry official as "highly serious" - language used in international safety circles as indicating there could have been an accident.

Boeing shares fell 2 percent in after-hours trading to $72.80 after the FAA announcement.

(Additional reporting by Olivier Fabre, Kentaro Sugiyama, Mari Saito, Yoshiyuki Osada, Deborah Charles, Tim Hepher, Anurag Kotoky, Jaroslaw Kowalski, Danilo Masoni and James Topham; Writing by Ben Berkowitz; Editing by Gary Hill)