A U.S. Marine Corps F-35B Lightning II assigned to Marine Fighter Attack Squadron 121 taxis on a runway at Andersen Air Force Base, Guam, Jan. 26, 2025. (Johnny Diaz/U.S. Air Force)

A Marine Corps F-35B Lightning II that made a precautionary landing at a Japanese airport more than three weeks ago is still undergoing maintenance, the service said Tuesday.

The stealth jet, assigned to Marine Fighter Attack Squadron 121 at Marine Corps Air Station Iwakuni, landed at Kochi Airport on the afternoon of March 25 after the pilot received a warning indication during a routine training flight, 1st Marine Aircraft Wing spokesman Maj. Joseph Butterfield said at the time.

As of Tuesday morning, the jet remained parked at the airport in Kochi prefecture, where it is undergoing parts replacement and maintenance, Butterfield told Stars and Stripes by email that day.

No timeline has been set for its return to MCAS Iwakuni, said Butterfield, who declined to provide further details, citing security concerns.

“The aircraft’s onboard systems worked as designed and alerted the pilot to a potential issue, and the pilot responded as trained to ensure safe flight operations,” he wrote. “We will continue thorough inspections of the aircraft to ensure its safe return to home station.”

Kochi prefecture is on Shikoku, the smallest of Japan’s four main islands.

Commercial flights at Kochi Airport have not been affected by the F-35B’s presence, a spokesman for the airport said by phone Tuesday.

The aircraft will depart the airport once it is safe to do so, a spokesman for the Chugoku-Shikoku Defense Bureau said by phone. He did not provide additional information.

Some Japanese government officials customarily speak to the press on condition of anonymity.