PARIS — A man opened fire outside a Jewish school in southwest France on Monday morning, killing four people, three of them children, and wounding another, officials said.

Witnesses said that a man fled the scene in Toulouse on a motorbike.

Michel Valet, the local prosecutor, said a father, his two children and another child were killed in the attack and a 17-year-old boy was seriously wounded.

“He shot at everything he could see, children and adults, and some children were chased into the school,” Mr. Valet said, according to news reports.

President Nicolas Sarkozy, interrupting his presidential campaign, arrived in Toulouse late Monday morning. His Socialist opponent, François Hollande, also suspended his campaign and planned to travel to the site of the shootings.

Last week, in the same region, a man on a motorbike killed three French paratroopers in two separate shootings, using a pistol of the same caliber as one of two weapons used in the Toulouse killings, police officials said.

“There are some similarities but it’s much too early to say if there is a real link or not,” Mr. Sarkozy said, according to Agence France-Presse. “Only the police and the judiciary will tell us what conclusions to draw.”

He called the shooting a “national tragedy.”. . .