Two more people have been arrested in connection with the attacker who killed 84 people in the French Riviera city of Nice on July 14, a source close to the investigation told Reuters.
Paris prosecutor Francois Molins said last week the Bastille Day attacker, Mohamed Lahouaiej Bouhlel, had been planning the attack for months.
Five suspected accomplices already in custody have been put under formal investigation, though none of them had been known to intelligence services.
The source said the new arrests took place on Monday in Nice. No other details were immediately available.
Islamic State has claimed the Nice attack, calling Bouhlel one of its soldiers, but authorities say they have yet to find evidence that the 31-year-old, who was shot dead by police, had any actual links to the militant group.