European leaders are to discuss measures to ease the region's migration crisis, with Turkey the focus of their efforts in Brussels, according to BBC News.

Nearly 600,000 migrants have reached the EU by sea so far this year, most via Turkey, says the International Organisation for Migration. Turkey is thought to be hosting some two million migrants, most of them fleeing the war in neighbouring Syria.

EU leaders are seeking closer co-operation with Turkey. They are keen for the Turkish government to sign up to a joint action plan. In exchange, Turkey would undertake various measures including implementing asylum procedures and giving priority to "the opening of the six refugee reception centres built with the EU co-funding".

Ankara, however, is expected to press for more rapid progress towards visa-free travel for its citizens to European countries that have abolished border controls within the so-called Schengen area.

Ahead of Thursday's meeting in Brussels, the EU Council President Donald Tusk has warned that concessions will be granted only if Turkey helps reduce the influx of migrants, which stands at a record level.

German Chancellor Angela Merkel is expected in Ankara for talks at the weekend.