Stockholm: Swedish police arrested four people on suspicion of preparing a terror attack and evacuated an arts centre in Sweden`s second largest city on the eve of the 9/11 anniversary, officials said on Sunday.
The four were arrested in the west coast city of Goteborg and were suspected of plotting terrorism, security police spokesman Stefan Johansson said, declining to give other details.
It wasn`t immediately clear whether the arrests were linked to the 10-year anniversary of the September 11 terrorist attacks in the United States.
Police in Goteborg said in a statement they had evacuated an arts centre in the city overnight Sunday due to a threat deemed to pose "serious danger for life, health or substantial damage of property”.
They said they had assisted security police with the arrest and declined to give any further comments.
Mia Christersdotter Norman, the head of the Roda Sten arts centre in Goteborg, said about 400 people were celebrating the opening of an international biennial for contemporary art when police ordered everyone to leave the building.
"Around midnight I was called out by the police and they said there was a threat to the building and asked us to quietly stop the party, which we did and everyone left," Christersdotter Norman said.
"Police have searched the building but they didn`t find anything," she said, adding the arts centre would reopen as usual on Sunday.
She said she had no information about the arrests, and had not been aware of any threats against the arts festival or its participants before the police operation.
Sweden raised its terror threat alert level from low to elevated in October last year. In December, suicide bomber Taimour Abdulwahab blew himself up in downtown Stockholm among panicked Christmas shoppers, injuring two people, causing shock in a country that had largely been insulated from terrorism.
The 2007 drawing of the Prophet Muhammad by a Swedish cartoonist raised tensions in Sweden. In May, Lars Vilks was assaulted while giving a speech in Uppsala, and vandals unsuccessfully tried to burn down his home in southern Sweden. His cartoon was reportedly the inspiration for Abulwahab`s attack.
In a report detailing the extent of extremist Islamist networks in Sweden, ordered months before that attack, the SAPO security agency had downplayed the risk of terror attacks in the Nordic country. Activity among radicalised Muslims in Sweden is primarily directed toward supporting militants in other countries, including Somalia, Afghanistan and Pakistan, it said.
Scandinavia has largely been focused on Islamic terrorism since September 11, but in the wake of Norway`s terrorist attack by a right-wing anti-immigrant Norwegian, the European police agency said it was setting up a task force of more than 50 experts to help investigate non-Islamist threats in Scandinavian countries.