French President Emmanuel Macron called the trafficking of African migrants a "crime against humanity''

 On Tuesday as he began an African visit in Burkina Faso with his first major address on the continent.Macron proposed a crackdown on human smugglers' networks between Africa and Europe after video footage broadcast on CNN this month showed the auction and sale of migrant men as slaves in Libya.Migrants hope to survive an often deadly voyage across the Mediterranean from the chaotic nation.

Macron said he wants "Africa and Europe to help populations trapped in Libya by providing massive support to the evacuation of endangered people." He did not elaborate, saying he will formally detail his proposal at a summit of the European Union and the African Union in Ivory Coast on Wednesday.

The footage has prompted widespread outcry across West Africa, where many migrants pressured by climate change and high unemployment set off in search of a better life.Already Burkina Faso's foreign affairs minister has recalled his ambassador from Libya, calling it "unacceptable to have slaves in this 21st century."

Concerns about the treatment of migrants are expected to feature prominently at this week's summit. Also high on the agenda is regional security, including the growing threat of Islamic extremism.

Macron is urging international support for a new military force that includes Burkina Faso and four other regional countries and is meant to counter a growing jihadist threat. Burkina Faso has seen two attacks on restaurants popular with foreigners, including one in August that killed 18 people.

The threat was underscored late on Monday by an attempted assault on a French military vehicle just hours before Macron's arrival. Authorities said two people on motorcycles had intended to use a grenade to attack a bus carrying French military members. The assailants missed their intended target but several people nearby were wounded, police said. Also on Tuesday, the French presidency's spokesperson said stones were thrown at a vehicle transporting members of the French delegation accompanying Macron's visit, despite heavy security.

Bruno Roger Petit said on his official Twitter account that Macron was meeting with his Burkina Faso counterpart, President Roch Marc Christian Kabore, at the time. No vehicle was destroyed and there were not "hundreds of assailants."

In his first major Africa address at the University of Ouagadougou, Macron sought to refocus the France-Africa dynamic away from a colonial past.

The 39-year-old president said he is the child of "a generation that has never known Africa as a colonised continent," and he stressed the "undeniable crimes of European colonisation."

Macron also said he wants conditions to be met in five years so that pieces of African cultural heritage can return to African museums "temporarily or definitively," saying that "I cannot accept that a large part of African heritage is in France."

The French leader also referred to his comments that prompted controversy in July, when he suggested that it's a problem when African women have "seven or eight children." He said on Tuesday that "I want a young girl to have the choice not to have children at the age of 13" and that "When you see families of six, seven, eight children per woman, are you sure it's a choice from the girl?"

After Macron's visit to Ivory Coast for the summit he will make a stop in Ghana before returning to France.