A boat used by refugees and migrants to travel across the Aegean Sea from the Turkish coast is seen on a beach, on the Greek island of Lesbos, in this November 21, 2015 file photo. [Photo/Agencies]

ISTANBUL - At least 18 people attempting to reach Greece drowned after their boat sank off the Turkish coast on Sunday, the state-run Anadolu news agency reported, on the eve of a European meeting aimed at tackling the number of migrants.

The Turkish Coast Guard, using speedboats and a helicopter, rescued 15 people and recovered 18 bodies in the Aegean Sea near the town of Didim, Anadolu said. Efforts continued to find more victims whose nationalities were not given.

Turkish Prime Minister Ahmet Davutoglu will be in Brussels for Monday's emergency summit with European Union leaders seeking to reduce illegal migration to member states, much of which occurs through Turkey.

"Turkey has been carrying this burden pretty much on its own for five years," Davutoglu told reporters at a news conference on Sunday before his departure. "But since the second half of 2015, this matter has become part of the Europe Union's agenda, and we are pleased with the sensibility Europe has displayed and its willingness to work together."

The EU has offered Turkey 3 billion euros ($3.3 billion) to do more to stop migrants from attempting the perilous journey. The migrant crisis has divided the EU's political leaders and threatened the bloc's open-border policy.

So far this year, 135,000 migrants have reached Europe illegally, 126,000 via Turkey, and more than 400 have died, many on the so-called eastern Mediterranean route from Turkey to Greece, the International Organization for Migration has said.

Last year, a million people reached Europe through illegal routes, many fleeing economic and political turmoil in the Middle East, North Africa and Asia. Most of them came through Turkey, which borders Syria, Iran and Iraq.