MANILA, Philippines (AP) — The Philippine navy and coast guard are searching for 20 crew members of a cargo ship that may have sunk in rough waters west of the main island of Luzon.

Coast guard spokesman Lt. Cmdr. Algier Ricafrente says the Hong Kong Maritime Rescue Coordinating Center reported late Friday that it had received a distress call from the MV Oceanic Union off Ilocos Norte province.

He says the ship may have sunk or was sinking since the crew had already abandoned ship.

A navy vessel and a coast guard vessel, helicopter and airplane are scouring the waters about 100 miles (160 kilometers) west of Burgos township. Other ships passing through the area have been notified.

The Panamanian-registered ship was heading to Subic Bay west of Manila from Shanghai.