The police presence outside Jewish sites in France would be increased following the explosion, the minister added. Darmanin and Attal were to travel to the site of the explosion on Saturday.
La Motte’s mayor, Stephan Rossignol, said that CCTV had picked up images of an individual setting fire to the cars.
The blast occurred during Shabbat, the Jewish day of rest that runs from sunset Friday to sunset Saturday and often when many attend synagogue services.
There was, however, no religious service ongoing at the time of the incident, a police source said.
Two doors of the synagogue were damaged in the blast.
There was no immediate information about the gravity of the police officer’s injuries.
The town near Montpellier has about 8,500 permanent residents but the population swells during the summer tourism season.
The explosion comes amid a heightened state of alert in France and other European countries because of the war in Gaza.
Darmanin said this month that the government had counted 887 anti-Semitic acts in France in the first half of 2024, nearly three times as many as in the same period in 2023.
France is home to the biggest Jewish population outside Israel and the United States, and also to the largest Muslim community in the European Union.
The Representative Council of Jewish Institutions in France (CRIF) called the explosion “an attempt to kill Jews”.
The use of a gas canister “in a car at a time when worshippers are expected to arrive at the synagogue is not simply a criminal act”, CRIF president Yonathan Arfi told AFP. “This shows an intention to kill.”
Police have locked down the area around the synagogue.
