The 613 men had traveled from their native Niger to neighboring Libya, where many of them planned to reach Europe over the Mediterranean Sea, a journey thousands of people from sub-Saharan Africa endeavor to make every year.

But late last month, the men were deported by Libyan authorities in one of the country’s largest expulsions in years. The mass deportation is part of a common pattern: North African governments, funded by the European Union to tackle migration, using brutal tactics to block sub-Saharan Africa migrants from heading to Europe.

The 613 men reached Niger’s closest town to the Libyan border on Jan. 3, disheveled and hungry, some barefoot and sick after months of detention and days of travel across the Sahara. Two of the men died shortly after arriving in Niger.

“I lived through hell,” said Salmana Issoufou, one of the men. Mr. Issoufou, 18, said he had been beaten by Libyan prison guards with wires and weapons throughout his eight-month detention.

As anti-migrant sentiment rises across Europe, from France to Germany to Hungary, the citizens of sub-Saharan Africa trying to reach the continent are being pushed back by North African governments in proportions unseen in years. The E.U. has signed bilateral agreements with Tunisia, Morocco, Libya, Mauritania, that include financial support to curb migrant flows.

The strategy appears to be working: illegal border crossings dropped sharply in 2024, according to recent data from the European Union’s border agency, Frontex.