Two years after militants killed 130 people in coordinated attacks across Paris, French officials say the county faces an unprecedented “internal” threat from battle-hardened ISIS fighters coming back to France.

Although the Islamic State has lost tremendous ground in Iraq and Syria, officials fear hundreds of French citizens could launch local attacks in the name of the terrorist organization -- leaving authorities unsure of how to contain the threat.

French President Emmanuel Macron will pay tribute on Monday to the victims of the mass shootings and suicide bombing that occurred across Paris and in the city’s northern suburbs on Nov. 13, 2015.

The deadliest attacks on French soil since World War II prompted the country to join international military operations against ISIS and other terrorist groups in Iraq, Syria and elsewhere.

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French police stand guard outside Notre Dame Cathedral after a shooting in Paris in June of 2017. (Reuters)

Lawmakers also passed legislation giving French police extended powers to search properties, conduct electronic surveillance and close mosques or other locations suspected of being breeding grounds for radicalism and hate.

France also recently unveiled a new program called Research and Intervention in Extremist Violence, targeting people already sentenced or awaiting sentencing on terrorism-related charges, for de-radicalization through mentoring.

According to France24, a group of 14 people will meet on an individual basis over the course of a year with a team that includes coaches, a psychologist, a religious adviser and a psychologist in an effort to rid them of any propensity toward extremist violence.

More than 30 attacks in the last two years have been thwarted, French police report.

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French prosecutor Francois Molins told Reuters that while bigger cells are still plotting, more attacks are likely to come from isolated individuals using “low-cost” methods such as cars or knives to kill.

“We are witnessing a new bout of isolated actions, 11 since the beginning of the year, which supports the idea of an increasing endogenous threat,” Molins told franceinfo radio.

French police are seen on patrol in Paris after a terrorist attack in November of 2015. (AP)

Molins also said that French authorities estimate that around 690 French nationals are now in Iraq and Syria, including some 295 women.

“A majority doesn’t want to come back to France given the legal proceedings they face upon their return,” Molins told the French radio station. “But some women, widows, with their children, are inclined to travel back. We should not be naïve. We are dealing with people who are more ‘disappointed’ than ‘sorry.’”