ATHENS, Greece (AP) — Greece's coast guard says a search and rescue operation is underway for a boat believed to be carrying about 50 migrants which issued a distress call off the coast of the eastern Aegean island of Samos.

The coast guard said Wednesday one helicopter and six vessels, including coast guard patrol boats and ships from the European border agency Frontex, were searching for the boat north of the island of Samos. The search was mounted after authorities received a phone call by one of the boat's passengers saying the vessel had run into unspecified trouble.

Hundreds of migrants and refugees continue to arrive on Greek islands each week from the nearby Turkish coast, while others cross the river that runs along the land border between the two countries.