A Spanish coast guard vessel intercepted on Saturday a boat packed with 13 Moroccan migrants, including four minors, about 10 nautical miles (18.5 kilometres) off the coast of the southern province of Granada.
The migrants, all of them male, were taken to a local detention centre which has seen its numbers swell since the end of August due to a wave of arrivals of boats from Morocco carrying people seeking a better life in Europe.
Last month a man was found dead clinging to a flimsy vessel adrift at sea off the Spanish exclave of Ceuta which borders Morocco, and a dozen more migrants were missing and feared dead, after their boat capsized during an attempt to reach Spanish soil.
Eleven African migrants, including three women and two children, died in April when their wooden boat capsized off the Spanish coast.
The drama faced by migrants trying to sail to Europe's shores has been pushed to the top of the political agenda after a boat carrying between 450 and 500 African asylum-seekers — mostly Somalis and Eritreans — capsized on Thursday off the remote Italian island of Lampedusa.
French Prime Minister Jean-Marc Ayrault called Saturday for a meeting of European countries on border management in the wake of the disaster in which hundreds are feared dead.
The Spanish government has warned that fighting in the Sahel region of northern Africa and the unrest sparked by the Arab spring uprising has increased the flow of migrants.
The numbers of migrants who have attempted to reach Spain's southern shores from Morocco by boat has increased since August, due in part according to Spanish authorities to the end of the Islamic holy month of Ramadan.
"This year the region that has had the greatest number of rescues is Tarifa," said Carmen Lorente of Spain's maritime rescue service.
Tarifa is located only 15km (nine miles) from Morocco across the Strait of Gibraltar.
It has become one of the key smuggling routes for illegal migrants crossing into Europe after Spanish authorities a decade ago cracked down on migrants heading to Spain's Canary Islands in the Atlantic off the coast of Morocco.
Authorities estimate thousands of illegal migrants from Africa regularly attempt to cross from Morocco into Spain on makeshift boats each year.
Some travel thousands of miles overland, being handed from smuggler to smuggler, ending up at one of many ports in northern Africa for a cramped and treacherous sea crossing to European soil.
Overall the number of migrants who have been rescued at sea while trying to enter Spain is down in 2013 over last year despite the rise in attempted crossing in recent weeks.
Spain's maritime rescue services have picked up 1,396 migrants from boats off the coast of Spain between January 1 and September 16, compared to 1,709 during the same period last year, Lorente said.
But the number of rescue operations has risen this year since migrants are making the perilous trip in smaller boats, often in inflatable dinghies that carry fewer people, she added.
Thousands of migrants also try to enter Spanish soil overland by scaling the border fences that surround Ceuta and Melilla, two Spanish exclaves surrounded by Morocco that have the European Union's only land borders with Africa.
The most spectacular recent attempt took place on September 17th when about 300 migrants tore down part of the three rows of six-metre-high (20 foot-high) fencing that surrounds Melilla and about 150 made it through.
Police video images showed dozens of migrants scrambling over the fence and starting to run as soon as they hit Spanish soil.
Six Spanish police officers and one immigrant were injured in that border assault.