PARIS (AFP) - French Prime Minister Manuel Valls said Tuesday that 110 extremists who left French territory to fight with the ISIS group had died in Iraq and Syria.

"More than 860 individuals have spent time in these countries, 471 of which are still there and 110 of which are dead," Valls told the Senate as it studies an intelligence bill approved by lawmakers in May.

Nine of those died in suicide bombings, said Valls.

France, along with Belgium, has seen the largest numbers of citizens or residents leaving to join ISIS (Islamic State in Iraq and Syria), which has seized large parts of Syria and Iraq.

The phenomenon has raised fears that radicalised citizens may return to carry out attacks on home soil.

A new intelligence bill giving the state sweeping powers to spy on its citizens has been in the works for some time but gained impetus after a extremist killing spree in January in Paris left 17 dead.

It is now before the upper house Senate, dominated by the right-wing opposition UMP which has just been renamed The Republicans.

Valls defended the bill which has been criticised for being overly intrusive, and said intelligence gathering "would target people who present a real threat to our security."