French security forces are preparing for mass civil unrest and radicalized immigrants taking over entire neighborhoods, according to intelligence sources.

The Army is making contingency plans for the “reappropriation of national territory,” winning back areas of cities, in the event of immigrant populations obtaining weapons and becoming openly hostile to authorities.

“There are a lot of alienated and angry fourth-generation immigrant kids in the suburbs and the prospect of radicalisation is increasingly likely,” the intelligence source told the Telegraph, adding that highly organized networks of Islamist militants have smuggled Kalashnikov automatic rifles and anti-tank missiles into the country.

The weapons were sourced in Libya after the French government armed jihadist rebels during the overthrow of Colonel Gaddafi.

The missiles could be used to bring down airliners, said the source, adding that pilots have not been trained on how to take evasive action.

Last week, a radicalized jihadist attempted to carry out a massacre on a high speed train from Amsterdam to Paris but was thwarted by the brave actions of three Americans and one Brit who overpowered the terrorist.

France is still reeling from the Charlie Hebdo attacks in January during which 16 people were killed by three radical Islamists.

A poll conducted last year found that a staggering 15 per cent of French citizens had a positive view of ISIS, with 27 per cent of people aged 18-24 expressing support for the terrorist outfit.

Many of the supporters are obviously drawn from France’s Muslim population of 5 million, which is the largest in the European Union per capita.

According to Yury Rubinsky, the head of the Center of French Studies of the Russian Academy of Sciences, support for ISIS amongst French Muslims represents, “a manifestation of the country’s accumulated potential rejection of the existing system as a whole. This is a form of rejection of the elites, a form of protest.”