Dutch police were on Thursday investigating possible terror links after arresting a Spanish man driving a van containing gas canisters close to a rock concert which was abruptly canceled due to a threat of an attack. The man "was arrested and taken to the police station," Rotterdam police said in a tweet late Wednesday, following a tip-off from Spanish authorities. Dutch bomb squad officials "were investigating the van" which was found just two streets away from the Maassilo concert hall where an American rock band were due to play, they added. The arrest came little under a week after twin vehicle attacks in Spain killed 15 people, which were claimed by ISIS. Earlier in the evening Dutch authorities decided to cancel the concert by Californian group Allah-Las in Europes largest port city after a tip-off from Spanish police around 5:30 pm about a possible terror attack. "In the early evening I was warned by telephone that we had received a threat which had implications for an American concert at the Maassilo in Rotterdam," the citys mayor, Ahmed Aboutaleb, told a hastily-called press conference. "This signal came from the Spanish police to the Dutch police," he added. But Aboutaleb, the countrys first Muslim and immigrant-born mayor who has spoken out against terror groups, added an investigation was underway and "we cannot say now if the van with the canisters was linked to the threat". The four-piece band, from Los Angeles, had been escorted from the concert hall by police wearing bullet-proof vests. Rotterdam police said that afterwards an officer "stationed close to the venue decided to stop a van that he saw driving at around 21:30 hrs". "The van had Spanish plates and was driven by a Spanish national. Inside the van were a couple of gas bottles. Whether there is a link with the terror threat is being looked into," the statement in English said, adding "the driver was taken into custody".  The international connections of the cell of mostly Moroccan nationals behind the Spanish attacks are being probed as investigators retrace their movements to France and Belgium. Spanish police carried out new raids overnight Tuesday to Wednesday after vehicles ploughed into pedestrians on Barcelonas busy Las Ramblas boulevard and a seaside promenade in the resort town of Cambrils. Fifteen people were killed and more than 120 others were wounded. Spanish court documents have shown that at least 500 litres of acetone, large quantities of nails and detonators as well as gas canisters were found in raids on a house in the town of Alcanar, south of Barcelona. The Rotterdam building where Wednesdays concert was to be held, which can hold about 1,000 people, was searched by the Dutch anti-terror squad after the crowd had been evacuated. The National Coordinator for Security and Counterterrorisms office said the threat level in the Netherlands was unchanged at "substantial", where it has been since 2013.