(CNN)Libyan authorities have launched a formal investigation into slave auctions in the country following an exclusive CNN report earlier this week, the government's Anti-Illegal Immigration Agency said Friday.
CNN's Nima Elbagir, Raja Razek and Alex Platt traveled to Libya in October after obtaining footage of a migrant auction.
At a property outside the capital of Tripoli, CNN witnessed a dozen men being sold like commodities -- some auctioned off for as little as $400.
CNN was told of auctions at nine locations across Libya, but many more are believed to take place each month.
Libya has long struggled to cope with an influx of migrants from sub-Saharan Africa, many of whom hope to transit in Libya before traveling to Europe with the help of smugglers.
Estimates from the United Nations put the number of migrants in Libya at 700,000. For years, migrants crossing the Mediterranean have brought with them stories of beatings, kidnapping and even enslavement.
Many of them make harrowing journeys from West African countries. Those migrants who do make it to Europe are often too terrified to go on the record about their ordeal.
CNN has also provided the evidence of slave auctions in Libya by unscrupulous smugglers to the Office of the Prosecutor at the International Criminal Court.