THESSALONIKI, Greece (AP) — Greek authorities have begun transporting about 1,500 asylum-seekers from the eastern Aegean island of Lesbos to the mainland, as part of government efforts to tackle overcrowding in refugee camps and a recent spike in the number of people arriving from the nearby Turkish coast.

A ship carrying 635 people set sail from Lesbos Monday morning for the northern port city of Thessaloniki. From there, authorities said the asylum seekers would be transported to a camp in Nea Kavala in northern Greece. A second ship carrying around 900 people was to leave Lesbos for Thessaloniki on Monday afternoon.

The transfer was part of decisions made during a national security meeting Prime Minister Kyriakos Mitsotakis convened Saturday, after nearly 600 people arrived on Lesbos in the space of an hour on Thursday.