ATHENS, Greece (AP) — Greek authorities have launched a search and rescue operation off the coast of the eastern island of Chios after a dinghy transporting migrants from the coast of Turkey sank early Tuesday.

The coast guard said 20 people had been rescued and a further seven were believed to still be missing.

A rescue helicopter and two coast guard vessels as well as nearby private boats were taking part in the operation.

Greece was the main entry point for refugees and migrants entering the European Union during the 2015-16 crisis but the number of arrivals has dropped sharply over the past two years in part due to tougher policing measures. The EU border protection agency, Frontex, has also stepped up support for the Greek border guard and coast guard.