On Thursday evening, 73 men from Mali were handcuffed and flown from Melilla to Algeciras, on the Spanish mainland, where they were they put aboard a ferry bound for the Moroccan city of Tangiers, a police spokesman in Algeciras said.
There were no plans for more deportations on Friday, he said.
They were the first group of immigrants to be expelled after Spanish authorities on Wednesday announced that they would send back Africans who made it from Morocco to Melilla - an enclave on Morocco's northern coast.
Morocco has promised shelter, medical care and humane treatment for deported immigrants, the official MAP news agency reported on Friday, citing the Interior Ministry.
However, the humanitarian organisation Medecins Sans Frontiers, or Doctors without Borders, reported that at least 400 Africans captured by the Moroccan army at forests near the Melilla border have been taken to a desert without any assistance, water or food.
"The immigrants have been forsaken by the world, abandoned in the middle of the desert," said Carlos Ugarte, a Madrid member of the organisation. He said pregnant woman and children are among the 400.
Waves of men
For the past week, increasing waves of men from impoverished, sub-Saharan African nations seeking entry in Europe have charged guard posts along the borders separating the centuries-old Spanish enclaves of Melilla and Ceuta from Morocco.
Six men died on Thursday during a violent assault by 400 immigrants trying to enter Melilla.
A EU mission has left for Morocco
to discuss illegal immigration
Last week, five people died of bullet wounds when some 600 Africans tried to climb fences and reach the other enclave, Ceuta.
Meanwhile, a European Union mission left for Morocco and the Spanish enclaves there on Friday to assess the problem of illegal immigration into the EU, officials said.
"We are dealing with an incredibly difficult situation, it is not easy to handle," said Friso Roscam-Abbing, a European Commission spokesman.
"The purpose of this mission is to look at what happened and what we can do in the future to make sure this doesn't happen again."
In Geneva, the UN refugee chief on Friday said that his agency was in talks with Spain and Morocco, to ensure that genuine refugees among hundreds of people trying to storm Spain's North African enclaves get a fair hearing.
"We have been in close consultations with the Spanish government on this," said Antonio Guterres, the UN High Commissioner for Refugees.
"We are also in contact with the Moroccan authorities. We are preparing a mission that will go very soon to Morocco, hoping that the situation can be dealt with in an adequate way," he said.
"According to our mandate, what we are entitled to is to make sure that those in need of protection are in fact granted access to the adequate procedures."
Pressure on Algeria
In Rabat, a Moroccan diplomat said the EU must put pressure on Algeria to prevent African illegal immigrants from crossing its territory into Morocco en route to Europe.
Morocco has become a destination for migrants and is no longer just a transit country, Menouar Alem, Rabat's ambassador to the EU, said in remarks published in L'Economiste daily.
"(Algeria) is not deploying any serious effort to control thousands of sub-Saharan Africans who enter Morocco from Maghnia (western Algerian area)"
Morocco's EU ambassador
"If the EU continues to ignore the origin of African expatriates and especially the country of transit that is Algeria, then this problem of immigration will not be solved," Alem said, adding that 80% of would-be immigrants came from sub-Saharan Africa.
Alem said the EU was not pressing Algeria hard enough to prevent sub-Saharan Africans from entering Morocco.
"(Algeria) is not deploying any serious effort to control thousands of sub-Saharan Africans who enter Morocco from Maghnia (western Algerian area)," Alem said.