At least 21 people have gone from France to Iraq to join the anti-coalition fighters since the U.S.-led invasion in 2003, national police said Thursday.

National Police Chief Michel Gaudin told The Associated Press that nine of them had been killed, and 10 were believed to be alive and still in Iraq.

CountryWatch: France

Five of those killed were French citizens, while the other four had traveled to Iraq from France. "We are working with international authorities to determine their identities," Gaudin said.

Two more French people were in custody after having been detained by coalition forces operating in Iraq, a national police spokesman said.

Gaudin, speaking on the sidelines of a meeting of European and African interior ministers in Nice, called for a broader approach for preventing the flow of militants from France to Iraq.

French counterterrorism officials uncovered and dismantled four suspected feeder networks of French nationals for the insurgency in Iraq last year.

Islamic militants from France have participated in armed struggles and received battle training around the globe, in places such as Chechnya, Bosnia and Afghanistan, authorities say. Anti-terrorism officials have warned of the growing threat of Islamic extremists returning to France from Iraq's battlegrounds with the skills and desire to carry out attacks in Europe.