At least 20 people died in boats carrying migrants trying to reach the EU south of Greece's island of Crete, the coast guard said on Monday.

The migrants' bodies were found in two vessels, with eight dead people being found on one and twelve on the other.

Another 40 people were rescued from both vessels, the authorities in Greece said.

It was not immediately clear who the 20 people were nor the circumstances under which they died.

According to Greece's coast guard, one of the boats was found sailing about 15 nautical miles — about 28 kilometers or 18 miles — south of the southern Mediterranean island of Crete on Monday morning.

Busiest migrant route

Greece has for a long time remained one of the main entry points for refugees and migrants from the Middle East, Africa and Asia.

During the period of 2015-2016, Europe faced a major migrant crisis and since then Athens has increased its maritime and border patrols. However, the number of migrants coming from northeastern ⁠Libya ​migrants attempting to enter Europe through Crete has surged.

Despite irregular border crossings into the EU going down by a third this year, the eastern Mediterranean was the busiest route for migrants trying to enter the bloc's territory, Frontex said in October.

The route's busiest section was from Libya to Crete, with the eastern Aegean islands and the land border with Turkey following.

Many of the vessels that carry migrants trying to reach Europe sink or encounter trouble along the way, posing a major risk for migrants' lives.