French citizens among radical fighters in Mali, minister says (File) A cartridge lies on the floor next Malian soldiers on February 22, 2013 in Gao, northern Mali. A Frenchman found among jihadists in Mali is being extradited, French official says His arrest follows that of a French-Algerian man last weekend, he tells French radio Defense minister: Northern Mali has been a sanctuary for al Qaeda-linked terrorists Nearly 4,000 French troops are deployed in Mali, alongside 6,300 from an African-led force (CNN) -- A Frenchman was captured among jihadists fighting international forces in northern Mali and is being extradited to France, the French defense minister said Friday. French forces are dealing with "determined terrorists" in Mali, said Defense Minister Jean Yves Le Drian, speaking to French radio station Europe 1 from the African nation's capital, Bamako. Mali: The long, troubled desert road ahead And the presence of the French citizen among them, as well as a French-Algerian man who was arrested last weekend, demonstrates how northern Mali had become a magnet for extremists, he said. "This shows that there existed a kind of terrorist war network, which would welcome young people in search of a radical destiny, as some have done in Afghanistan or Syria," he told the radio station. The French-Algerian man, who was sought by French police, was detained by Malian officers in northern Mali, Le Drian said. He was extradited Thursday to France, he said. Read more: What's behind the instability in Mali? We knew that this part of Mali was potentially the sanctuary of al Qaeda in the Islamic Maghreb. We were not mistaken, this is the case," Le Drian said. We are dealing with determined terrorists, who are heavily armed and who are waging significant battles and inflicting major damage. Nearly 4,000 French soldiers are now deployed in Mali, according to the French Defense Ministry website, alongside about 6,300 troops from Chad and the African-led International Support Mission to Mali. Q&A: What's behind the instability in Mali? In the past few weeks, French and African forces have helped Malian troops drive the militants out of their strongholds in the north, including cities like Gao, Kidal and Timbuktu. Some of their number are believed to now to be hiding out in remote mountains near the border with Algeria. French troops are continuing to "comb" through the Adrar des Ifoghas Mountains for the militants, French Foreign Minister Laurent Fabius said Thursday, and are keeping a strong presence in Gao, where "important pockets of terrorist groups remain." France is using DNA tests to identify the Islamist fighters killed in recent battles in northern Mali, Fabius said. Those tests could establish whether Moktar Belmoktar or Abdelhamid Abou Zeid -- two men who have been major forces in al Qaeda in the Islamic Maghreb -- are among the dead, as has been suggested by others but not confirmed by France. France will begin to reduce its troop levels in Mali next month in an effort to have West African forces, with the support of the United Nations, take over and maintain security in the country, Fabius said.