PARIS (Reuters) – France said on Monday it had foiled a terrorist plot and arrested seven people, a year after a state of emergency was imposed to counter a wave of Islamist attacks.

Interior Minister Bernard Cazeneuve said the seven people of French, Moroccan and Afghan origin, aged 29 to 37, were detained on Sunday. One of the detentions followed a tip-off from a foreign government, he said.

Two were arrested in the Mediterranean port city of Marseille and four in Strasbourg in the northeast. Cazeneuve did not say where the seventh was arrested.

“Yesterday, a terrorist act on our soil that was being prepared for a long time was foiled thanks to the work of the DGSI,” Cazeneuve said in a statement, referring to the internal intelligence service.

“The scale of the terrorist threat is enormous and it is not possible to ensure zero risk despite everything we are doing.”

French soldiers patrol past wooden barracks shops during the installation of the traditional Christkindelsmaerik (Christ Child market) near Strasbourg’s cathedral in Strasbourg, France, November 21, 2016. REUTERS/Vincent Kessler

The minister gave no information on the target of the planned attack. The mayor of Strasbourg said it appeared the plot had not concerned his city but rather “the Paris region”.

A source close to the inquiry told Reuters that some of those detained had spent time in the Syria-Iraq region.

Security is a major theme in campaigning ahead of France’s presidential election next spring.

More than 230 people have been killed in attacks on French soil since January, 2015, when Islamist militants killed 17 people in Paris in an attack on the satirical newspaper Charlie Hebdo.

Gunmen and suicide bombers killed 130 people in coordinated strikes in Paris last November 13.

Islamic State, whose strongholds in Syria and Iraq are being bombed by warplanes from an international coalition including France, has urged followers to continue attacking the country.

Le Parisien newspaper cited a source as having told it the suspects arrested were awaiting a consignment of weapons.

(Reporting by Brian Love, Matthias Blamont and Chine Labbe; Editing by Richard Lough and Andrew Roche)