Japanese and US investigators are conducting a probe of the maker of the lithium ion batteries used in Boeing's grounded 787 jets.
Tsutomu Nishijima, a spokesman for GS Yuasa, said Monday that the investigators visited the company's headquarters in Kyoto, Japan and that Yuasa was cooperating with the probe.
He said he could not comment on details of the investigation or on whether it would continue beyond Monday. Transport Ministry officials also would not immediately comment on the investigation or its findings.
After an overheated battery forced an emergency landing of an All Nippon Airways 787 flight last week, all 50 787s that Boeing has delivered to airlines have been grounded. The manufacturer has halted deliveries of new planes until it can address the electrical problems.