A French security official says a 19-year-old woman linked to gas canisters found in an abandoned car near Paris' Notre Dame Cathedral had pledged allegiance to the Islamic State group.

Security in train stations around Paris was visibly higher Friday as the investigation into the car widened.

The woman, Ines Madani, was injured in the leg and arrested after a standoff Thursday night with police in Boussy-Saint-Antoine, south of Paris.

The security official, who was not authorized to be publicly identified, said French authorities have a document in which Madani declares allegiance to the extremist group.

Another official, who also cannot be identified, said one of the women pulled a knife and stabbed a police officer during the arrest.

Five women and two men have been arrested in the case.