The African Union (AU) has expressed outrage after video footage released by CNN last week shows sub-Saharan migrants being sold at slave markets in Libya. On the video, young men are seen being auctioned off as farm workers.

The AU chairman, Guinea President Alpha Conde, demanded prosecutions over a “despicable” trade “from another era”.

As reported by the BBC, migrants trying to reach Europe have spoken of being held by smugglers and forced to work for little or no money.

“These modern slavery practices must end and the African Union will use all the tools at its disposal,” Conde said.

Libya has opened an investigation into the practice, CNN reported on November 17.

In April, the International Organization for Migration (IOM) said it had gathered evidence of slavery in Libya.

The IOM’s chief of mission for Libya, Othman Belbeisi, told the BBC at the time that migrants were priced according to their abilities.

“Apparently they don’t have money and their families cannot pay the ransom, so they are being sold to get at least a minimum benefit from that,” he said.

“The price is definitely different depending on your qualifications, for example if you can do painting or tiles or some specialised work then the price gets higher.”

In related news, the Agence France-Presse (AFP) noted that African migrants from nations including Guinea, Senegal, Mali, Niger, Nigeria and Gambia make the dangerous crossing through the Sahara to Libya with hopes of making it over the Mediterranean Sea to Italy.

But testimony collected by AFP in recent years has revealed a litany of rights abuses at the hands of gang leaders, human traffickers and the Libyan security forces, while many end up stuck in the unstable north African nation for years.

More than 8,800 stranded migrants have been returned home this year, according to the IOM, which is also amassing evidence of slavery.