ATHENS, Greece (AP) — A migrant boat sinking in the eastern Aegean between Greece and Turkey left at least 16 people dead, including two children, Greek authorities said Monday, while two people were rescued. Patrol boats and helicopters were searching for several more people believed missing.

Greece’s coast guard said the bodies of nine people – six women, two men and a child – had been recovered from Greek waters off the island of Lesbos, while Turkish authorities found the bodies of a further six men and a child in Turkish waters.

One of the rescued women was pregnant. She told Greek authorities she had been among roughly 25 people who had set sail late Sunday night from the Turkish coast heading to Lesbos. The U.N. refugee agency, UNHCR, said one of the women was believed to be from Congo and the other from Cameroon.

Vessels and helicopters from Greek authorities and Europe’s border patrol agency Frontex were participating in a search-and-rescue operation, while private boats were also helping in the effort. The alert was raised Monday morning by a Greek navy vessel that spotted bodies in the water.

“The number of people crossing the Aegean to Greece has dropped drastically over the past year, but this tragic incident shows that the dangers and the risk of losing one’s life remain very real,” UNHCR’s Greece representative Philippe Leclerc said in a statement.

Hundreds of thousands of migrants have crossed into Greece from the nearby Turkish coast, hoping to head to more prosperous European countries. But a European Union-Turkey deal reached last year – in which those arriving on Greek islands face deportation back to Turkey – has significantly reduced the number of people attempting to cross the Aegean.

Most undertake the short but dangerous journey on overloaded inflatable dinghies or occasionally sailboats. It was unclear what type of smuggling vessel was used Monday, or how it ran into trouble.