ATHENS, Greece (AP) — Forty-two people have been rescued while another three are missing after a boat believed to have been carrying migrants sent out a distress call while sailing in the Mediterranean south of the Greek island of Crete, the Greek coast guard said Thursday.

Officials said they were alerted by the Italian coast guard overnight about a boat in distress 27 nautical miles (31 miles, 50 kilometers) south of Crete. Greece’s coast guard said 40 people were rescued by ships that had been sailing in the area, while another two people were later rescued by a Greek navy helicopter.

The coast guard said survivors have told them that there are three others still missing, and that officials are conducting search and rescue operations in the area. It was not immediately clear what kind of vessel the passengers had been on, or why the boat sent out a distress call.