Los Angeles folk-rock band Allah-Las were forced to cancel a concert in the Dutch port city of Rotterdam after police reported a terror threat in the area.

The driver of a van with Spanish license plates that contained a number of gas tanks was detained close to the Maassilo venue and was being questioned by police, according to Rotterdam Mayor Ahmed Aboutaleb. Military explosives experts were also sent to examine the vehicle.

Aboutaleb said the terror warning stemmed from Spanish police, who notified Dutch authorities. The Dutch police then alerted the venue, which shut down the show. He declined to give further details on the nature of the warning or where in Spain it came from, but said it was too early to link the van directly to the terror threat. Spanish police are currently investigating the attack in Barcelona that killed 13 people and injured more than 100 others.

The concert had not yet begun when the decision was made to cancel it.

Reports indicate the band is unharmed, and Dutch television showed what appeared to be the band members leaving the site in a van, while Dutch police in body armor congregated at the venue.

The concert organizer, Rotown, assured fans on Twitter that they would get their money back, after posting that the concert would be canceled after the police’s warning.

The incident is still under investigation, and Allah-Las have not yet made any public statements following the cancellation.