MADRID (Reuters) - Spain’s coast guard rescued 933 migrants and found four dead bodies in the Mediterranean Friday and Saturday, as the country prepared for the arrival of a charity rescue ship that was denied a port by Italy and Malta.

The number of people fleeing poverty and conflict by boat to Spain doubled last year and is likely to rise again in 2018, according to the EU border agency, potentially pushing migration up the national political agenda.

Spanish Prime Minister Pedro Sanchez has already made migrant-friendly moves in his first two weeks in the job, offering to take in the rescue ship Aquarius with 629 people on board and pledging free healthcare to undocumented migrants.

The coast guard said on Twitter it had rescued 507 people from 59 small dinghies in the Gibraltar strait, where it also found the four bodies.

All the other rescues happened in the Alboran Sea, between northeastern Morocco and southeastern Spain.