French authorities have confirmed that three women arrested in connection with a car filled with gas cannisters being left near Notre Dame cathedral were planning to attack a Paris railway station this week.
France's interior ministry said: "An alert has been issued to all stations but they had planned to attack the Gare de Lyon on Thursday."
Gare de Lyon is a station three miles from Notre Dame cathedral, where the car was discovered on Saturday.
The boyfriend of one of the women was detained overnight, bringing the number of people being held over the alleged plot to five.
French President Francois Hollande said: "A group has been destroyed, but there are others. An attack has been foiled."
The youngest of those held, aged 19, is said to have written a letter pledging allegiance to Islamic State.
Shouts of 'Allahu Akbar' were heard on video footage of the women's arrests.
One of the women - thought to be the teenager - stabbed a police officer during her arrest before being shot and wounded.
TV footage showed a policeman leaving the scene of the arrests on the outskirts of Paris carrying a large knife.
The officer's injuries are not life-threatening.
The car also contained three jerry cans of diesel and was found with its hazard lights on.
Interior minister Bernard Cazeneuve said: "These three women aged 39, 23 and 19 had been radicalised, were fanatics and were in all likelihood preparing an imminent, violent act."
The 19-year-old's father was arrested and later released after reporting his daughter had gone missing with the Peugeot 607 car.