ATHENS, Greece (AP) — Greece's coast guard says 12 migrants have been found dead in the Ionian Sea and 21 others have been rescued after their boat took in water and sank. Searchers are looking for more survivors.

The deaths and sea rescues came southwest of the Greek island of Paxos, a coast guard spokesperson told the Associated Press, speaking on customary condition of anonymity because of the ongoing investigation.

“The initial report is that 50 people were in the boat,” he said.

The coast guard said someone from the boat had called the 112 emergency number at 9:15 a.m. Saturday. At least four merchant ships, six coast guard ships and a helicopter were searching for survivors amid calm seas.

No further information about the migrants was released.