File photo: French crime scene investigating police place bags of evidence inside a car parked outside the five-storey apartment building where earlier special forces police staged the assault on the gunman Mohamed Merah, in Toulouse on March 22, 2012.

Paris -

French police on Tuesday arrested four people as part of an investigation into the supply of jihadists to the Sahel region of Africa, Interior Minister Manuel Valls said.

French radio reports said one Malian and three Franco-Congolese binationals were arrested in the raids in the Paris area.

Valls told BFM television the operation followed the arrest a few months ago of a man caught travelling between Mali, where French and African forces are currently fighting Islamist militants, and neighbouring Niger.

He estimated at “a handful” the number of French nationals fighting alongside al-Qaeda-linked militants in the Sahel region of North and West Africa and “several dozen” those fighting alongside insurgents in Syria.

“We're fighting an external and an internal enemy,” Valls said.

French police and intelligence services have been on the lookout for homegrown radicals with terrorist ambitions since 2012's attacks by Toulouse native Mohamed Merah. Merah, who claimed links to al-Qaeda shot dead seven people, including three Jewish schoolchildren. - Sapa-dpa