At least four migrants died in the eastern Aegean Sea when a small boat bringing them from nearby Turkey sank just off the island of Samos, Greek authorities said.

The coast guard said five other people were rescued after the accident, but it was unclear how many had originally been on the boat and whether any more were missing.

The bodies of four women were found during a large search and rescue operation involving three coast guard patrol boats, a private vessel and an air force helicopter.

Crews also searched on land in case survivors had managed to reach the shore.

The coast guard said a number of migrants were later located on Samos, but it was not immediately clear whether they were survivors from the shipwreck or had arrived separately.

It was not known how the boat, believed to have been a small dinghy, sank, and there was no immediate information on the identities or nationalities of the survivors and the dead.

Greece lies along one of the most popular routes into the European Union for people fleeing conflict and poverty in the Middle East, Africa and Asia.

Despite a crackdown by Greek authorities along the land and sea border with Turkey, thousands of people make it across, often from the Turkish coast to Greek islands using flimsy inflatable dinghies.

In recent months, smugglers have also increasingly turned to ferrying migrants in powerful speedboats.