ISTANBUL, June 17 (Xinhua) -- Thirty-one illegal migrants were rescued but nine others went missing on Monday when their boat sank off Turkey's Aegean coast.

The inflatable boat carrying a total of 40 refugees capsized near the Bodrum district in the southwestern province of Mugla, the Turkish coast guard said in a statement posted on its website.

Rescue operations are continuing to find the missing refugees, the statement added.

The Aegean Sea was once a main route for migrants fleeing into Europe via Turkey. A deal signed between Turkey and the European Union in March 2016 has helped reduce the flow of illegal immigration.

Since this year, a total of 10,855 migrants have attempted to reach Greek islands via Turkey, slightly down from 11,682 over the same period in 2018, according to figures released by the Turkish coast guard.