French police commandos arrested 19 people and seized weapons in Friday morning swoops on people suspected of radical Islamist activity, in several cities including Toulouse, scene of the killings of four Jews and three soldiers this month.
President Nicolas Sarkozy, who is waging an uphill battle for re-election in an April-May vote, said more such raids would follow.
There will be further operations, allowing us to expel a number of people who have no business in the country, he said in an interview on Europe 1 radio.
The raids come just over a week after al Qaeda-inspired gunman Mohamed Merah was killed by police snipers after shooting dead three Jewish school children, a rabbi and three soldiers in attacks around Toulouse, turning internal security into a bigger campaign issue ahead of the presidential election.
Polls showed that more than 70 percent of voters approved of Sarkozy's handling of the crisis, which reduced his chief rival, Socialist frontrunner Francois Hollande, to the role of bystander ahead of the two-round election on April 22 and May 6.
A police source said about 20 had been arrested in swoops in Toulouse in the southwest, Nantes in western France and also in the Paris region and southeast France.
Sarkozy put the number of arrests at 19 and said the police had seized weapons including Kalashnikov assault rifles.
The swoops, carried out by the RAID police commando unit and anti-terrorist specialists, were not directly related to Merah's killing spree, according to the police source.
The police source said that Friday's raids were not directly related to the investigation into the case of Merah, a Frenchman of Algerian origin, whose brother Abdelkader has been placed under official inquiry and is being held in custody on suspicion of complicity.
The same police source said several of the people arrested were believed to be close to a radical Islamist group called Forsane Alizza that was recently outlawed.
Several guns and a bullet-proof vest were seized in Friday's raids, another police source said.
(Reporting by Gerard Bon and Brian Love; Writing by James Regan and Brian Love; Editing by Mark Heinrich and Geert De Clercq)