MADRID, Spain (AP) _ Police detained 186 would-be immigrants aboard four boats off the southern coast of Spain early Wednesday after a body washed ashore, authorities said.

The four boats, carrying migrants from Morocco and countries in sub-Saharan Africa, were found approaching Spain off the coast of the southern town of Tarifa.

In a routine search of beaches near the town, police found the body of one man they believe drowned while trying to swim ashore from one of the boats.

Once identified, the immigrants will be deported to their country of origin, police said.

Thousands of Africans attempt to reach Europe by crossing the Strait of Gibraltar at night in single-motor boats, often fleeing poverty and war. Many drown in the attempt.