Spain's maritime rescue service says it has saved 94 migrants attempting to cross the Mediterranean Sea from African to European shores.

The service says that it picked up the migrants from four boats intercepted either in or near the Strait of Gibraltar during Friday night and Saturday morning.

The United Nations says 636 migrants have died crossing the Mediterranean so far this year.

A total of 22,439 travelers reached Europe, 4,409 of them arriving in Spain, during the first four months of 2018.