Police in Rotterdam are trying to establish if there is a link between a terrorist threat at  city concert hall and a van with Spanish number plates containing gas bottles, the city’s mayor Ahmed Aboutaleb told a news conference on Wednesday evening.

Earlier, the mayor cancelled a concert by an American group Allah-Las at the city’s Maassilo concert venue following a tip-off from Spanish police that it may have been targetted.

Aboutaleb said he was informed about the terror threat by Spanish police towards the end of the afternoon. The threat said that an attack would take place during the performance by the Californian band and the tip-off was serious enough to merit cancelling the concert, he said.

As yet, no link has been established between the van and the threat, and Aboutaleb warned about jumping to conclusions. It could also be a plumber or welder who was in the neighbourhood, he said.

The van, which was stopped after being spotted driving around the same area not far from the concert venue is now being inspected by explosives experts. The driver has been arrested and is being questioned, the mayor said.

The Dutch counter terrorism agency NCTV said later that the terrorist threat level in the Netherland is not being increased and remains at four on a scale of one to five.

In June there was a major terror alert during a concert by Guus Meeuwis after a man was spotted hanging around the entrance to the stadium in Eindhoven. He was arrested but released several days later.

Het verdachte Spaanse busje in #Rotterdam met de glasflessen wordt op dit moment door de politie onderzocht. pic.twitter.com/Pq3aOxeTDX

— floor bremer (@floorbremer) August 23, 2017