PARIS — France was in mourning Monday after four people, including a father and his two sons, were gunned down at a Jewish school in the southern city of Toulouse, bringing the number of people killed by a gunman or gunmen in the area to seven within a week.

The killer struck shortly after 8 a.m., as children were arriving at Ozar Hatorah secondary school, which is situated next to a synagogue.

Alighting from his scooter, he opened fire on children and parents assembled outside the school, pursuing one child into the schoolyard, where he continued firing with a second weapon after his revolver jammed, before fleeing on the scooter.

“He fired on everything in front of him, whether parents or children,” Toulouse prosecutor Michel Valet said.

A 30-year-old religion teacher, his two sons ages 6 and 3, and the 8-year-old daughter of the school principal were killed. A 17-year-old boy was taken to hospital in a critical condition.

One parent who witnessed the attack said the man was “shooting at point-blank range, not even a meter away (from his victims).”

French President Nicolas Sarkozy called the attack a “national tragedy” and announced a minute of mourning in all schools on Tuesday.

“We don’t know the motivations of this criminal,” he said. But in “attacking Jewish children and a teacher, the anti-Semitic motivation seems clear,” Sarkozy said.

Israeli Prime Minister Benjamin Netanyahu said in a statement that, while it was “too early” to draw conclusions, he suspected “a strong murderous anti-Semitic motive.”

Sarkozy and Interior Minister Claude Gueant both said they suspected the killer of also being behind two attacks last week on soldiers in Toulouse and the nearby town of Montauban.

On March 11, a gunman also traveling by scooter shot to death a soldier in Toulouse whom he had arranged to meet under a false pretext.

Four days later, a man on a scooter opened fire on three soldiers on the street near a military base in Montauban, about 30 miles from Toulouse, killing two and seriously injuring a third. Two of the dead soldiers were of North African origin; the third was of Caribbean origin.

Police said the same pistol was used in all three attacks and that the registration plate of the scooter, as picked up by surveillance cameras at the school, matched that of the scooter seen speeding away from the scene of the Montauban attack.

Faced with the threat of further attacks, Sarkozy announced he was increasing the terrorist threat level in the Midi-Pyrenees region, which includes Toulouse, to scarlet _ the country’s highest level.

Gueant would lead the investigation, Sarkozy said, assuring gravely: “We will find him.”

Monday’s shootings comprise the worst attack on the Jewish community in France since 1982, when six people were killed in a grenade and shooting attack on a Jewish delicatessen in Paris.

“We were all very shocked,” a young schoolgirl told BFM TV, describing how parents and children huddled together in prayer after the attack.

On Monday evening, more than 1,000 people packed a synagogue in central Paris for a memorial service that was attended by Sarkozy and his wife, Carla Bruni-Sarkozy.

Sarkozy’s Socialist rival in next month’s presidential election, Francois Hollande, and his partner also attended the service.

In Toulouse, meanwhile, members of the Jewish community were attending a wake of the victims’ bodies at the school.

Security has been stepped up around Jewish schools and synagogues across the country.

France’s chief rabbi, Giles Bernheim, said he was “horrified” by the attack. The White House condemned an “unprovoked and outrageous act of violence”.

The motive for the attacks remains a mystery. French media have speculated the gunman may be a disgruntled former soldier or a right-wing extremist.

Toulouse Mayor Pierre Cohen said all public celebrations had been called off in the city this week for fear the gunman might strike again.

“There’s a sense of anxiety,” he said.