PARIS — Four suspects have been arrested in the southern French city of Montpellier in connection with plotting a terrorist attack in France, the country's interior ministry announced Friday.

Among the suspects were a 20-year-old man and a 16-year-old girl, both known to French authorities for ties to radical Islamist organizations. The attack had apparently been planned for Paris, according to the details of an investigation by France’s federal prosecutor.

“The initial indications are that an imminent attack on French soil has been thwarted,” French Interior Minister Bruno Le Roux said in a statement. The French government said that it foiled 17 similar plots last year.

The news of the arrests emerged a week after a 29-year-old Egyptian man wielding a machete charged soldiers outside the Louvre museum in Paris, chanting “Allahu Akhbar” or “God is Great” in Arabic. One of the soldiers was lightly injured, and the assailant was shot and seriously injured.

The attack at the Louvre, one of the most popular tourist destinations in the French capital, only served to exacerbate anxieties about security and terrorism in a city still reeling from the terrorist attacks in November 2015, when 130 were killed in a series of assaults coordinated by the Islamic State on a concert hall, cafe terraces and a stadium.

In September, French authorities said they foiled a plot to attack tourists and others outside of Notre Dame Cathedral in Paris in which a group of suspected terrorists had planned to detonate gas canisters in the pedestrian area in front of the church.

Tourism, which accounts for more than 7 percent of France’s gross domestic product, has declined significantly in the wake of recent terrorist violence, including the July 2016 attack in Nice, when a man inspired by the Islamic State plowed a truck into crowds gathered to celebrate the country’s national holiday. In that incident, 86 were killed. According to French media, an estimated 750 million euros ($795 million) has been lost because of trips canceled by overseas travelers.

Authorities have announced plans to increase security at the most iconic tourist destination in France, and among the most popular in the world: the Eiffel Tower, visited by roughly 6.8 million people every year. On Thursday — six days after the Louvre attack — authorities announced a major security overhaul at the Eiffel Tower. Already regularly patrolled by a special military squadron known as Operation Sentinelle, the site will now be surrounded, in certain areas, by a security fence.

According to Le Parisien newspaper, which first reported the project, the fence would be bulletproof and could rise to as high as eight feet, which immediately caused concern among certain Paris city councilors, who likened the new addition to a “bunker.”

Officials said the details remain negotiable, but construction is slated to begin before the end of the year.