Some of the 16 suspected Islamic militants detained in France allegedly planned to kidnap a Jewish magistrate and other people, a source close to the investigation said on Tuesday.
"It looks like some of them planned to carry out kidnappings including that of a magistrate who has a Jewish-sounding name," the source said.
Another source confirmed that a Jewish magistrate from Lyon in central France was to be targeted.
The head of France's Central Directorate for Domestic Intelligence, Bernard Squarcini, said on Saturday that those arrested the previous day were French nationals involved in "collective war-like training, linked to a violent, religious indoctrination".
Some of those arrested belonged to a suspected extremist group called Forsane Alizza, he said, and had been involved in paintball gun games.
Forsane Alizza chief Mohamed Achamlane was on Monday transferred to Paris where he was to appear before anti-terror magistrates who already extended the custody of 15 other suspected Islamists arrested on Friday.
French anti-terrorism legislation allows for suspects to be held for four days, or until Tuesday.
Three of the 19 people arrested on Friday have already been released, and those still in custody could be charged later Tuesday. Paris prosecutor Francois Molins was to hold a press conference around midday Tuesday.
The alleged militants were netted in anti-terrorist swoops in different French cities a week after self-confessed Al-Qaeda militant Mohamed Merah was shot dead following his killing spree in which he killed seven people.
The French opposition has criticized the presence of television news cameras during the arrests as the images could be seen to bolster the chances of right-wing President Nicolas Sarkozy's re-election later this month.
