As the Islamic State group and Boko Haram gain ground in north and east Africa, rebel groups linked to Al Qaeda are threatening to expand internationally. The rebel groups are fueled almost entirely by the money made in the human and drug trafficking networks throughout the Sahel region, experts say, and can gain access to countries such as Ivory Coast and Mauritania with relative ease.

“The trafficking is critical to their functioning,” said Hilary Matfess, a researcher with the Johns Hopkins University School of Advanced International Studies. “They get their funding through providing protection to drug convoys in the Sahel region and kidnapping for ransom.”

There are dozens of rebel groups in Mali, some connected to the ethnic Tuareg rebel movement, others connected to Al Qaeda in the Islamic Maghreb (AQIM), a branch of the broader Al Qaeda network. Several of the Tuareg rebel groups dominant in the north signed a peace deal with the government this month, both sides promising to put down their weapons. But other groups, specifically those connected to AQIM, made no such promise and are now, more than any other time since the beginning of the year, attacking outposts and convoys of the Malian military and the country’s UN peacekeeping mission.

On Thursday, six UN peacekeepers were killed in an attack by rebels in Ansar al Dine in Timbuktu, an area that the rebel group moved into in 2012 during the political unrest in the country that lead to a coup d'état. All of the peacekeepers were from neighboring Burkina Faso.

The northern part of Mali is still an area of concern for Malian officials, but the southern part of the country is also becoming more violent, especially within the past two weeks. One rebel group, Ansar al Dine, is ramping up its attacks near the capital.

Ansar al Dine, which the United States designated a terrorist organization in 2013, formed during the Malian political turmoil of 2012. The group follows the Saudi-inspired Salafist/Wahhabism Muslim ideology, even though most of the people in Mali identify with the Sufi sect -- often defined as a faction of Islam that follows the inner, mystical aspects of the religion

Although Ansar al Dine and AQIM have remained isolated from the rest of the Muslim extremist movement taking over much of North Africa, experts say that could soon change as the human trafficking network swells.

Each year thousands of migrants from places such as Sierra Leone, Niger, Burkina Faso and Mali pay up to $500 for a smuggler to take them north to Libya, where they get on a boat and head to Europe. This year, a record number of migrants have tried to make the journey to Europe, the UN said this week. In April, more than 900 people died after their boat capsized in the Mediterranean Sea.  

Many of those migrants crossed through Mali before reaching Libya. The northern city of Gao is the main hub for human and drug trafficking in Mali. In fact, according to a report by the BBC, the local economy there actually depends on trafficking.

But just as the locals there rely on money from migrants desperate to find a way to Europe, terrorist groups like Ansar al Dine and AQIM are dependent on the smugglers.

Matfess said her research shows that smugglers have to hire AQIM rebels to provide them with security as they travel through the Sahel region, especially in places like Mauritania. One U.K. convoy, Matfess said, discovered and intercepted a convoy in Mauritania; smugglers said that it costs them up to $50,000 per trip to travel through AQIM-controlled lands safely.

AQIM rebels get paid a transit fee that amounts to 10 percent of the value of each convoy, whether it is filled with humans or drugs.

The growing human trafficking network this year has allowed AQIM groups to recruit more fighters, provide them with salaries, and buy more weapons. The newfound strength within AQIM is threatening the borders of Ivory Coast and Mauritania.

Ansar al Dine attacked towns on Mali's borders with both countries this past week, and leaders of the group say they are planning more raids. The group’s new threat prompted forces from Ivory Coast to carry out a mission inside Mali Wednesday to try to track down the rebels who are thought to be hiding in the Sama forest.

Statements by the group’s leaders and the attacks carried out by rebels within the past week mimic those of groups like Boko Haram, the Nigerian militant group that is trying to expand from its land in Borno State into Cameroon and Chad.

The growing rebellion in the southern part of Mali comes just over one week after the Malian government and semi-moderate ethnic Tuareg rebel umbrella group signed a peace deal in Bamako. The two parties signed the deal after years of international pressure from Algeria, France and the U.N. peacekeeping mission in the country. The peace deal calls for the creation of elected regional assemblies but stops short of autonomy or federalism for northern Mali, known by locals as Azawad.

The peace deal solidified the Tuareg rebels' control in the north and forced groups like Ansar al Dine to look south.

Leaders of Ansar al Dine told Agence France-Presse that the group would “multiply the attacks in Ivory Coast, Mali and Mauritania” and accused all three countries of collaborating with “the enemies of Islam.”

The attack on its border prompted Ivory Coast lawmakers to schedule a vote on new anti-terrorism legislation that could give the government greater powers to track militant networks.

Although the governments of Ivory Coast and Mali are implementing stricter security measures on their borders, some experts question whether Ansar al Dine and AQIM have the ability to carry out international attacks.

Mia Bloom, an expert on terrorism from the Center for Terrorism and Security Studies at the University of Massachusetts Lowell, said Mali's rebel groups lack the sophistication emulated by other groups such as Boko Haram in Nigeria. "They are still pretty isolated," Bloom said.