A unusual attack by bees in the French town of Aurillac has left 24 people injured, including three in critical condition, according to local authorities.

The Prefecture of Cantal, in south-central France, said passersby were stung over a period of about 30 minutes on Sunday morning. Firefighters and medical teams were rushed to the scene to treat the victims while police set up a security perimeter until the bees stopped their attack.

The three people in critical condition were evacuated to a local hospital.

Pierre Mathonier, the mayor of Aurillac, told French broadcaster France 3 the incident may have been related to Asian hornets threatening beehives that had been installed on the roof terrace of a downtown hotel over 10 years ago. He said that this had likely caused the bees to become aggressive.