At least 21 migrants drowned off Turkey on Tuesday after their boats overturned in rough waters in two separate incidents as they tried to reach the Greek island of Lesbos, authorities and news reports said.

Nine bodies washed up on a beach in the resort town of Ayvalik early on Tuesday, prompting authorities to dispatch coast guard boats and gendarmerie officials to search the area by sea and by land for possible survivors. By late morning, the death toll reached 14, the coast guard said, adding that seven other migrants were either rescued or found alive.

Hours later, the private Dogan news agency reported that seven other bodies had washed up on shore at Dikili, a resort about 50 kilometers (30 miles) south of Ayvalik, the victims of a second migrant tragedy. The dead included women and children, the agency said.

Around 850,000 migrants and refugees crossed into Greece last year, paying smuggling gangs to ferry them over from Turkey in frail boats. Hundreds have lost their lives during the crossings.

The International Organization for Migration said an estimated 3,770 people died crossing the Mediterranean Sea last year, making 2015 the deadliest year on record for migrants and refugees trying to reach Europe.

Namik Kemal Nazli, the local administrator for Ayvalik, told the state-run Anadolu Agency that the victims of the first incident are believed to be from Iraq, Algeria and Syria. There was no information on the nationalities of those drowned in the second incident.

Nazli said were still searching for more migrants and that the death toll could rise further.

A body, still wearing a life jacket, was pulled from the sea onto the beach at Ayvalik by a fisherman and a military police official. Other bodies, also in lifejackets, were seen lying nearby.