Two vehicles parked outside a synagogue exploded in a French town on Saturday in what prosecutors called an act of terrorism.

The cars exploded outside the Ben Yacoov synagogue in La Grande Motte, a resort town on the southern coast of France. The synagogue’s doors were also set on fire, prosecutors said in a statement.

Five people, including the rabbi, were inside the synagogue at the time of the attack, around 8 a.m., as worshipers would have been making their way to the synagogue.

No one was killed, but one police officer responding to the explosions was hurt when a gas bottle inside one of the vehicles exploded, according to a statement from the antiterrorism unit in the prosecutor’s office.

Prosecutors are treating the attack as an attempted assassination by a terrorist organization intended to cause harm and destroy property, the antiterrorism unit said in its statement. No one had been arrested in the case as of Saturday afternoon.

The attack is likely to heighten fears of growing antisemitism in France, which has the largest Jewish population in Western Europe. Attacks against Jewish people in France have increased in recent years, and the government said it had recorded more than 360 antisemitic episodes in the first three months of 2024. The Israel-Hamas war has further heightened tensions in a society increasingly divided by religion and ideology.

President Emmanuel Macron vowed that the perpetrators would be tracked down, and that Jewish places of worship in France would be protected.

“The fight against antisemitism is a constant battle,” Mr. Macron said, adding that it was a fight for “a united nation.”

Officials in the municipality of Hérault, which includes La Grande Motte, said the city would be vigilant in protecting buildings associated with its Jewish community.

The municipality also canceled a demonstration planned for Saturday in nearby Montpellier by the Boycott, Divestment and Sanctions movement, which seeks to mobilize economic and political pressure on Israel over its treatment of Palestinians.

During France’s recent elections, the country’s left, particularly Jean-Luc Melénchon, the founder of France Unbowed, was accused of fanning antisemitism.

After Saturday’s explosions, Mr. Melénchon described the attack as an “intolerable crime” and called on France to uphold principles of secularism.