A bus driver in southern France was declared brain-dead Monday after being attacked by patrons who were denied entry for not wearing face masks, according to the BBC.

Bus driver in France left brain dead after being attacked by passengers who refused to wear face masks https://t.co/MaX4lpHIHV

— BBC News (World) (@BBCWorld) July 6, 2020

The driver denied several people entry after they failed to present tickets and refused to wear face masks while on the bus, per the BBC. The man, 58, reportedly sustained serious head injuries after being punched in the head. (RELATED: 20 People Making Religious Pilgrimage Reportedly Die After Train Hits Bus At Unmanned Railway)

Five people have been arrested in association with the attack, per France Bleu. The attack reportedly happened Sunday night in the southwest city of Bayonne after the bus driver left the bus to talk to a group of individuals. The mayor of Bayonne, Jean-René Etchegaray, told France Bleu that the attack was “an act of barbarism.” 

A report from France Bleu cites a Chronoplus statement claiming the driver was “beaten by several individuals,” but notes that authorities have not yet confirmed that statement. Authorities are reportedly still trying to understand exactly why the bus driver left the bus, what happened during the bus trip and how many people were involved. 

Chronoplus, the bus network that operates in the area of Bayonne, is out of service Monday as bus drivers are exercising their “right of withdrawal,” and gathered Monday morning at the bus depot “in support of their colleague,” per Sud Ouest. Bus drivers told Sud Ouest that there is a lack of security on the buses and daily tensions with users.

Face masks, according to the BBC, are mandatory on all public transit in France.