One US service member is missing and three others wounded but in stable condition after an MH-60S Seahawk helicopter made an emergency landing in the Arabian Sea, the U.S. military says, adding there is no indication the crash was caused by hostile action, Reuters reports.

“US Navy assets in the region are currently searching for other aircrewman still missing. The cause of incident is under investigation,” the US Navy’s Fifth Fleet says in a statement, adding that the helicopter was deployed to the region on the USS George HW Bush aircraft carrier.

Helicopter water landings can be dangerous, even for experienced pilots, given the propensity of top-heavy aircraft to flip upside-down during submersion. US forces in the region are also on high alert amid periodic flare-ups in violence during the ceasefire between the US and Iran.