A man on a scooter opened fire outside a Jewish school in Toulouse in southwestern France on Monday, killing two children and one adult, a police source said.
Five people were injured in the attack, which occurred as students were arriving for morning classes at the Ozar Hatorah school, a city official said.
The attack comes after three soldiers were killed in two separate shootings in the same region by a man who escaped from the scene on a scooter.
French interior minister Claude Gueant broke off a visit in northeastern France to head for Toulouse, the police source said. French media reported that security was being tightened at all Jewish schools in the country.
About 50 investigators are already looking into the killings of the two soldiers. Police said on Friday that the same weapon had been used in both incidents.
BFM TV news channel said that the gun used in the attack at the Jewish school was of the same calibre as that used in the soldiers' shootings.