Spanish authorities rescued over 500 migrants at the weekend from more than a dozen boats making the Mediterranean crossing to Europe.
Following plane and helicopter searches, Spanish boats rescued almost 300 migrants from nine boats on Saturday, authorities said. As of Sunday afternoon, a further 250 migrants were rescued from eight boats, three in poor condition which later sank, they added.
The migrants were from various countries in North and sub-Saharan Africa.
The number of people crossing into Spain by sea from North Africa, either via the Strait of Gibraltar or the Sea of Alboran, has increased significantly in recent years while arrivals to Italy and Greece via Libya have dropped.
Around 19,000 people made the sea crossing in 2017, representing a 182% increase on the previous year.
Europe border agency Frontex said in January it expected a further increase in irregular immigration to Spain this year, with flows boosted by the use of fast boats.
An Italian coastguard official said more than 1,800 migrants attempting to cross from Libya to Italy were rescued over the past three days, following an improvement in the weather.