A Boeing 737 cargo plane operated by K2 Airways has gone missing off Pakistan’s coast near Karachi, with five crew members aboard.

Pakistan’s Civil Aviation Authority said the aircraft lost contact with air traffic controllers late Tuesday. The airport authority reported that the crew had flagged a navigation system issue shortly before the plane’s communications failed. Radar data indicated the aircraft rapidly descended, and both radio contact and radar tracking were lost about 155 nautical miles west of Karachi.

Search-and-rescue efforts were launched immediately, with Pakistan’s Rescue Coordination Centre coordinating operations in the Arabian Sea. Pakistan Navy and Air Force assets were deployed, including maritime and aviation search platforms, as well as civilian shipping resources participating in the search.

Officials said the cause of the disappearance was not yet known, and no wreckage or survivors had been found at the time of reporting.