Concerns in Japan over the safety of the controversial Osprey aircraft have reignited following a U.S. decision to lift a global flight ban, despite Washington’s “unprecedented” information-sharing with Tokyo.

More than three months after a fatal crash in waters off Kagoshima's Yakushima Island, the U.S. said Friday that it plans to resume flights of V-22 Osprey tilt-rotor aircraft, but did not publicly offer specifics on the cause of the crash. Tokyo said that it is closely coordinating with Washington on a timeline for resuming operations in Japan, including of its own Ospreys, while signaling that it could soon sign off on the move.

At a news conference Monday, Chief Cabinet Secretary Yoshimasa Hayashi said that the crash was due to a "malfunction in a specific component," but did not offer further details.