Danish authorities have arrested and charged a 30-year-old Syrian asylum seeker living in Sweden, believed to have attempted a terrorist attack last November.

Danish police arrested the 30-year-old on Thursday in a joint operation that also involved members of the Danish intelligence services. So far they have failed to identify the suspect in custody, though they have suspicions that he was working with another suspected terrorist who was arrested in Germany, Reuters reports.

According to investigators, the man was working with another Syrian who was arrested last year at the Danish border with Germany after being found in possession possessing explosives, 17,000 matches, radio equipment, and an ignition device. The 20-year-old was charged with terrorism offences earlier this year and is believed to have links to the Islamic State.

According to Danish police, the man arrested Thursday had planned to join the arrested 20-year-old and attack random people with knives in Copenhagen, and potentially detonate several explosives.

Denmark Considers Tougher Border Controls with Sweden Because of Islamist Threat https://t.co/Pp3PAM8Aiu — Breitbart London (@BreitbartLondon) June 30, 2017

The arrest comes only months after the anti-mass migration Danish People’s Party and the Danish Conservatives announced that they would potentially back legislation to increase security along the Swedish border due to the threat of radical Islamic terrorism there.

Laura Lindahl, an MP from the ruling Danish Liberal Alliance, argued against stricter controls, saying: “There must be a real threat there to make it worth introducing border controls measured against the disadvantages this entails for ordinary people who every day cross the border to carry out their jobs.”

The number of radical Islamic extremists in Sweden has grown substantially over the course of the migrant crisis, with Swedish security agency Sapo claiming that there are at least 2,000 violent extremists in the country earlier this year.

Only seven years prior the number was around ten times lower, being estimated at roughly 200.