PARIS (AFP) - France's interior minister is Wednesday set to unveil a bill aimed at beefing up anti-terrorism laws and preventing aspiring jihadists from fighting abroad amid concern over the number of young nationals travelling to Syria.

The bill, part of which was seen by AFP, includes a ban on foreign travel by individuals suspected of being radicalised, for a duration of up to six months. It can apply both to adults and minors.

Under the proposal, their passports will be temporarily confiscated and invalidated.

Airlines will be banned from carrying targeted passengers and will have to notify French authorities the moment one of them makes a reservation.

If they do manage to go abroad, they will be the subject of an international arrest warrant.

The ban would be decided by the interior minister himself and could be extended as long as is necessary, the proposed bill says.

It also provides for tighter legislation against online recruitment, by for instance asking Internet service providers to block access to sites "that provoke acts of terrorism or praise them" - modelled on existing rules against child pornography sites.

It will also allow investigators to use pseudonyms to enter pro-jihadist sites.

The law will also be tightened to make individual plans of terrorism a punishable offence, aimed at those identified by authorities as "lone wolves".

Current legislation targets those who associate with a group suspected of planning or staging terrorist acts.

The French government is deeply concerned about the radicalisation of its nationals after hundreds of citizens have gone to fight with jihadists in Syria.

In May, authorities arrested Frenchman Medhi Nemmouche who is suspected of shooting dead four people at the Brussels Jewish Museum after spending a year fighting in Syria.

They have also deported a Tunisian accused of recruiting young jihadists to fight in Syria.

Interior Minister Bernard Cazeneuve will unveil the bill at Wednesday's weekly cabinet meeting.