Paris Prosecutor Francois Molins, right, with Director of the Judicial Police Mireille Ballestrazzi, left, addresses the media in Paris on Friday about a failed attack involving a car loaded with gas canisters near Notre Dame Cathedral. (Francois Mori/AP)

President François Hollande praised French security forces Friday for apprehending a group of terrorism suspects ­believed to be plotting a major attack.

An Interior Ministry official told the Reuters news agency that the foiled attack had been planned for the Gare de Lyon, a train station in the southeast quadrant of Paris that is one of the busiest in Europe.

“There’s a group that has been annihilated, but there are others,” Hollande said. “Information we were able to get from our intelligence services allowed us to act before it was too late.”

Still reeling from two major attacks in 2015, the French capital has been on edge since Sunday, when authorities found an abandoned car full of gas cylinders near Notre Dame Cathedral.

The area is a major tourist destination that frequently draws crowds to its pedestrian-friendly streets and sidewalk cafes, places similar to those near the seaside promenade struck in the July attack on Nice, in southern France, that killed 86 and injured hundreds more.

Police officers stand guard as they take part in a raid in Boussy-Saint-Antoine, east of Paris. (Thibault Camus/AP)

On Thursday, authorities arrested three women outside Paris in connection with the suspected plot — ages 19, 23 and 39. The youngest, identified by the Associated Press as Ines Madani, stabbed a police officer during the confrontation, officials told French media.

According to the RTL radio network, Madani had written a letter pledging her support to the Islamic State. The three women were apparently attempting to avenge the death of Abu Muhammad al-Adnani, the Islamic State’s lead propaganda officer killed in Syria in late August, RTL reported.

Before his death, Adnani had called on followers of the self-proclaimed caliphate to carry out small-scale attacks on “nonbelievers” in Europe and the United States, an injunction that became a reality in France and Germany this summer. In July, attackers inspired or claimed by the Islamic State slit the throat of a French village priest, stabbed tourists on a German train and shot at random in a Munich shopping mall.

According to the Le Monde newspaper, Madani had been known to authorities since 2015, when she unsuccessfully attempted to leave France for Syria, where thousands of foreign-born fighters had joined the Islamic State.

This week, France’s interior minister, Bernard Cazeneuve, announced that the flow of French citizens and residents decamping for Syria has significantly decreased, raising concerns about the possibility of more domestic attacks by would-be fighters who have opted to stay home as the Islamic State loses territory.

A police bomb disposal van arrives at the Gare de Lyon railway station in Paris, France, following the discovery of a suspect package, Friday, Sept. 9, 2016. (Francois Mori/AP)

As France struggles to formulate a strategy to prevent attacks of the type that appears to have been planned for the Gare de Lyon, analysts argue that a stronger intelligence infrastructure must be the primary focus.

In June 2015, largely in response to the attack on the Charlie Hebdo newspaper office, the French Parliament passed intelligence legislation that increased the government’s powers to monitor its citizens’ communications. But Jean-Charles Brisard, chairman of the Paris-based Center for the Analysis of Terrorism, said key provisions of the law — such as the pledged use of eavesdropping technologies and “black boxes” designed to catch threats sent electronically — have not been enacted, more than a year after the law was passed.

In the suspected plot, investigators found the car only after a shopkeeper reported it. It sat with its lights flashing for at least two hours, Florence Berthout, the mayor of Paris’s 5th arrondissement, where Notre Dame is located, wrote in a letter to the Paris Police Prefecture this week.

In total, seven suspects — two men and five women — have been arrested in the ongoing investigation into the foiled plot. According to an unnamed official quoted in an Associated Press report, one of the men arrested had ties to Larossi Abballa, who live-streamed the murder of a French police officer in June.

The car belonged to the Madani’s father, who later reported his daughter to French authorities