A speedboat carrying migrants capsized Friday morning off the eastern Greek island of Rhodes, leaving eight dead and 18 rescued, Greek authorities said.

The coast guard said the incident occurred while the speedboat was carrying out “dangerous maneuvers” to try and evade a patrol vessel, causing migrants to fall into the sea.

A rescue effort is underway involving coast guard vessels and a helicopter as it was unclear whether other passengers were missing, authorities said.

Rhodes, one of several large Greek islands located near the coast of Turkey, is on a busy illegal smuggling route in the eastern Mediterranean. It was the second deadly incident involving migrants in the past week, as authorities in Athens brace for a spike in arrivals as a result of wars in the Middle East.

Seven migrants were killed and dozens are believed to be missing after a boat partially sank south of the island of Crete over the weekend – one of four rescue operations during which more than 200 migrants were rescued.

The search south of Crete around the tiny island of Gavdos was called off Wednesday.

The number of migrants traveling illegally to Greece is expected to top 60,000 this year, with Syrians making up the largest number, followed by Afghans, Egyptians, Eritreans and Palestinians, according to government data.