ATHENS: At least two people died and 57 rescued when their boat overturned off the Greek island of Paros in the central Aegean Sea on Friday, the country's coastguard said.

Authorities scrambled a search and rescue operation north-west of the island of Paros, in what was thought to be the third shipwreck this week involving migrants in Greek waters.

Air and sea assets were deployed to the area, the coastguard said.

Greece's semi-official Athens News Agency reported that 80 people were believed to have been on the vessel, which it described as a sailboat. The circumstances under which it capsized were unclear, it said.

Earlier, Greek authorities said they had recovered 11 bodies from the scene of another shipwreck, when a sailboat carrying migrants sank off an uninhabited islet in southern Greece on Thursday.

Another 90 people were rescued in that operation. The coastguard said initial information suggested the migrants had been headed for Italy.

Greece is one of the main routes into the European Union for migrants and refugees from Africa, the Middle East and beyond, though the flow has tapered off since 2015-2016, when more than a million people traversed the country to other EU states.

Overnight between Tuesday and Wednesday a boat thought to have been carrying up to 50 migrants sank off the island of Folegandros, with dozens feared missing.