NEW DELHI (AP) — Rescuers searching for 22 missing sailors have found no trace of their Panama-flagged cargo ship after the vessel sank in the Bay of Bengal last week, the Indian Coast Guard said Tuesday.

Search aircraft and ships on Tuesday were scouring the area where the cargo ship MV Ocean Winner reportedly sunk Saturday about 276 miles (444 kilometers) from the Paradip coast of India’s eastern Odisha state.

The joint search by the Indian Coast Guard and Indian Navy has been complicated by the area’s exceptionally deep waters and found only an oil slick and two life rafts near the vessel’s last known position, officials said.

The lack of wreckage has hampered efforts to determine the cause of the sinking and where to focus search operations, authorities said.

The vessel transporting iron ore to China was carrying 24 crew members, including 20 Chinese nationals, three Myanmar nationals and one Bangladeshi, according to the coast guard.

Two Chinese crew members were rescued Saturday following a distress call from the ship, the coast guard said.