Japan's All Nippon Airways is in talks with U.S. aircraft maker Boeing to speed up the delivery of three 777 jetliners as its fleet of 787 Dreamliner airplanes remains grounded with undiagnosed battery problems, the Nikkei newspaper said on Sunday.

All 50 Boeing 787s worldwide remain grounded as authorities in the United States, Japan and France investigate a battery fire in Boston on Jan. 7 and a separate battery failure that forced a second 787 to make an emergency landing in Japan a week later.