PARIS (AFP) - Six people have been detained in France on suspicion of recruiting candidates for jihad, a judicial source said on Wednesday, as the number of French citizens travelling to Iraq and Syria increases.

The suspects, two of whom are minors, were held in the suburbs of the eastern city of Lyon as part of an "anti-terrorism" probe launched in July.

According to a police source, a brother and a sister are among those detained since Tuesday, and one of the suspects is linked to Forsane Alizza (Knights of Pride), an Islamist extremist group that had called for France to become an Islamic caliphate and was banned in 2012.

The detentions come amid concerns in France about the number of citizens travelling to Iraq and Syria to wage jihad.

According to Interior Minister Bernard Cazeneuve, around 930 French citizens have travelled to and from the two violence-ridden countries recently, a 74 per cent increase in eight months.

The country's Lower House National Assembly has been debating an anti-terrorism bill, of which a key measure is a travel ban on anyone suspected of "planning to travel abroad to take part in terrorist activities, war crimes or crimes against humanity or in a theatre of operations of terrorist groups".

The measure - which was approved by the National Assembly on Tuesday evening - would see suspects have their passports and ID cards confiscated for six months, renewable for up to two years.