Interior Minister Bernard Cazeneuve confirmed on Monday that police detained seven people of French, Moroccan and Afghan origin on Sunday. All of the suspects are aged between 29 and 37. Six of them were not previously known to intelligence services, and one had been flagged to France by a foreign government.

The raids were linked to a series of arrests in June during the European Championship soccer tournament that was held in cities across France, Interior Minister Cazeneuve said.

"An attack has been foiled ... The scale of the terrorist threat is enormous and it is not possible to ensure zero risk despite everything we are doing," Cazeneuve said.

Arrests in south and east

Two of the arrests were made in the southern port city of Marseille, while most of the others were made in Strasbourg neighborhoods of Neuhof and Meinau, where authorities dismantled a jihadi network in 2014. Included in the group was the brother of an Islamic State (IS) bomber who attacked the Bataclan concert hall in Paris last November.

Strasbourg - a tourist hotspot on the French-German border - is particularly popular in the winter months when it holds one of the oldest and largest Christmas markets, due to open on Friday. The historic city, which is also the official seat of the European Parliament, was previously the target of a failed extremist plot in 2000.

Target 'Paris region'

Although Cazeneuve did not dislclose the target of the attack on Monday, Strasbourg's mayor said the focus of the plot was "the Paris region," Reuters reported. The French capital has already been hit by two deadly attacks within the last two years, killing more than 140 people. A further 86 people were killed in July, in a separate attack in Nice.

According to the interior ministry, French police have detained 418 people this year in terrorism investigations following deadly Islamic State attacks.

ksb/kl (Reuters, AFP, AP)