At least six people ​died in a bus fire on Tuesday in ‌a small town in western Switzerland, prompting the police to launch a criminal investigation.

Fribourg city police said the bus became engulfed in ​flames on a road in Kerzers, a town in ​the canton of Fribourg, about 20 km ⁠from the Swiss capital, Bern.

“At this stage, we have elements ​suggesting a deliberate act by a person who was inside ​the bus,” said Frederic Papaux, a spokesperson for Fribourg police.

Three injured people were taken to the hospital, the police added.

Passengers were seen escaping from ​the burning bus, panicked and injured, Papaux said, adding ​that no other vehicle was involved.

Video after the flames were extinguished showed ‌the ⁠charred remains of the vehicle.

When asked about unverified social media reports that an individual on the bus had poured gasoline on themselves, Papaux said he could not confirm whether ​gasoline was used ​or how ⁠the fire had started.

Swiss President Guy Parmelin offered his condolences and said the incident was ​being investigated.

“It shocks and saddens me that ​once again ⁠people have lost their lives in a serious fire in Switzerland,” he said in a statement on X.

In January, Switzerland ⁠was ​rocked by a fire in a bar ​in the Swiss ski resort of Crans Montana that killed 41 people and ​injured 115.