ATHENS — Coast guard divers searched the hull of a submerged sailboat for passengers possibly trapped inside Friday after the vessel hit rocks off the coast of southern Greece and sank, leading to the deaths of at least seven people.

The Greek coast guard said 90 people were rescued overnight from a rocky islet some 235 kilometers (145 miles) south of Athens, near the remote island of Antikythera.

Smugglers based in Turkey increasingly have packed sailboats with migrants and refugees and sent them across the Mediterranean Sea toward Italy, avoiding the heavily patrolled Greek islands.

In a separate incident Friday, Greek police arrested three people on smuggling charges and detained 92 migrants after a yacht ran aground in the southern Peloponnese region.

A search operation also continued for a third day in the central Aegean Sea, where a boat carrying migrants sank near the island of Folegandros. Thirteen people were rescued, and the survivors reported that at least 17 others were missing. Authorities said the passengers originally were from Iraq.