Toulouse, France ? A motorbike assailant opened fire with two handguns Monday in front of a Jewish school in the French city of Toulouse, killing a rabbi, his two young sons and a girl. One witness described him as a man chasing small children and “looking to kill.”

One of the guns he used also had been fired in two other deadly motorbike attacks in the area that targeted paratroopers of North African and French Caribbean origin, officials said. French President Nicolas Sarkozy suggested one person was responsible for all the killings.

A massive manhunt was under way, and the terrorism alert level was raised to its highest level ever across a swath of southern France surrounding Toulouse. Hundreds of officers increased security at schools, synagogues and mosques around the country, and Sarkozy said 14 riot police units “will secure the region as long as this criminal” hasn’t been caught.

Monday’s attack revolted France and drew strong condemnation from Israel and the United States. Sarkozy called it the worst school shooting in French history.

France has seen a low drumroll of anti-Semitic incidents but no attack so deadly targeting Jews since the early 1980s. This country is particularly sensitive toward its Jewish community because of its World War II past of abetting Nazi occupiers in deporting Jewish citizens.

French prosecutors were studying possible terrorist links, but the motive for all three attacks was unclear. Still, issues about religious minorities and race have emerged prominently in France’s presidential campaign, in which the conservative Sarkozy has taken his traditional hard line against immigration.

News that the gun was used in attacks last week around Toulouse fueled suspicions that a serial killer was targeting not only Jews but French minorities.

In all three cases, the attacker came on a motorcycle, apparently alone, and then sped away.

Monday’s attack was as quick as it was terrifying. A 30-year-old rabbi, Jonathan Sandler, and two of his sons were killed just before classes started at the Ozar Hatorah school, a junior high and high school in a quiet neighborhood, Toulouse Prosecutor Michel Valet said. The Israeli Foreign Ministry said the sons were 4- and 5-years-old.

Another child, the 7-year-old daughter of the school principal, was also killed, school officials said. Valet said a 17-year-old boy was also seriously wounded.