The Greek coast guard on Wednesday said it was looking for dozens of migrants in the Aegean Sea after 12 people were rescued overnight.
Migrants regularly seek to reach mainland Greece from the Turkish Aegean coast, many in vessels that are not seaworthy.
What did the coast guard say?
Authorities said an operation began after the coast guard received information that a vessel carrying migrants had started taking on water south of the island of Folegandros.
It is believed the boat had suffered engine failure.
A coast guard official said rescuers found 12 people, mostly Iraqis, in a smaller auxiliary boat, but the rest were still missing. Only two of the rescued migrants were wearing life jackets.
"The 12 mostly Iraqi migrants ... were taken to Santorini. They are in good health," the official said. According to those rescued, there had been 30 to 50 people on the original vessel.
A spokesman for the coast guard told state-run ERT television that colleagues were presuming the worst-case scenario of 50 people having been on board.
Four coast guard vessels, two military helicopters and a C-130 transport plane were said to be participating in the search, as well as a number of passing ships and smaller private vessels.
Not the normal route
Greece is an initial destination on the route into the European Union for many asylum-seekers and migrants arriving from Turkey.
However, Folegandros, one of the southern Cyclades Islands, is not along a usual route for migrant smugglers.
Arrivals have dropped sharply since 2016 after the EU and Ankara agreed on a deal to stop migrants from making the potentially hazardous crossing.
The majority try to cross in dinghies but — with regular patrols and reports of illegal pushbacks and summary deportations back to Turkey — many also attempt lengthier routes on larger and often older vessels.