Ten people aged 32 to 69, including an ex-policeman, have been placed under formal investigation in France after weapons, including explosives were found at various locations over the weekend.
French judges have placed nine men and one woman under formal investigation on suspicion of planning attacks against Muslims, a judicial source said on Thursday.
Aged 32 to 69, the ten are suspected of plotting attacks against several targets, including imams. They include a 65-year old ex-policeman, thought to be the group's leader, and his wife.
Thirty-six weapons, a leaflet detailing how to make home-made explosives, and products that can be used to make bombs were found when the ten were arrested over the weekend at various locations in France, the prosecutor's office said on Wednesday.
Four of the activists will stay in custody pending trial, four were released and two are still waiting for a judge to decide their fate.
All ten are now under formal investigation over suspicion of "belonging to a criminal association in relation to a terrorist undertaking."
The investigation had led police to fear the group would move to take violent actions, the prosecutor's office said in a statement.
"The group was trying to recruit new members and extend its reach by structuring itself at the regional level," the statement said.