By Christian Hartmann and Ingrid Melander
BOUSSY-SAINT-ANTOINE/PARIS (Reuters) - Three women arrested on Thursday in connection with a car laden with gas cylinders found abandoned near Paris's Notre Dame cathedral were likely planning an imminent attack, French Interior Minister Bernard Cazeneuve said.
The minister said one of the women had stabbed a police officer during the arrest before being shot and wounded. A source close to the investigation said the attacker was the missing 19-year-old daughter of the car's owner.
The discovery on Saturday night of the Peugeot 607 loaded with seven gas cylinders, six of them full, prompted a counter-terrorism investigation in a country where militants have killed more than 230 people in attacks since January, 2015.
Police sources said no detonator had been found, though the vehicle also contained three jerry cans of diesel fuel, adding to concerns that there had been a plan to explode the car.
"These three women aged 39, 23 and 19 had been radicalised, were fanatics and were in all likelihood preparing an imminent, violent act," Cazeneuve said in a televised statement.
Seven people have now been detained since Tuesday in connection with the investigation.
The arrests took place in Boussy-Saint-Antoine, some 30 km (20 miles) south-east of Paris.
A Reuters photographer later saw a hand-cuffed person being carried into a building in that town, in the area cordoned off by police, where house searches were being carried out. Police investigators and bomb-disposal experts were on the ground.
The town's mayor told BFM TV there had been no specific threat of an attack in the local area.
The Peugeot was found in the early hours of Sunday morning on a Seine riverside road metres from Notre Dame cathedral.
Documents with writing in Arabic were also found in the car, which had no registration plates and was left with its hazard lights flashing.
The car owner was taken into custody earlier this week but later released. He had gone to police on Sunday to report that his daughter had disappeared with his car, officials said.
His daughter, officials say, is known to police for wanting to leave for Syria, where scores of religiously radicalised people of French and other nationalities have joined the ranks of the Islamic State militant group.
France, which is taking part in bombing the militant group's bases in Iraq and Syria, remains on maximum alert after calls for attacks on the country.
Thousands of extra police and soldiers have been deployed to patrol sensitive sites since 130 people were killed by Islamist gunmen and suicide bombers in attacks on Paris last November.
A state of emergency declared at that time is still in place and gives police extra search and arrest powers but debate still rages over security after another attack in July in which a man drove a truck into crowds in the city of Nice, killing 86.
(Additional reporting by Simon Carraud; Writing by Richard Lough; Editing by Ralph Boulton and Chris Reese)