STOCKHOLM – Swedish police arrested four people on suspicion of preparing a terror attack and evacuated an arts center in Sweden's second largest city on the eve of the 9/11 anniversary, officials said Sunday.
The four were arrested in the west coast city of Goteborg and were suspected of plotting terrorism, said Sara Kvarnstrom, spokeswoman for the Swedish security police, SAPO. She declined to give details on the arrests and wouldn't say whether they were linked to the 10-year anniversary of the Sept. 11 terrorist attacks in the United States.
Kvarnstrom said SAPO saw no reason to raise its terror alert level, which has been at "elevated" since October.
"Our assessment is that there is no reason for public concern at the moment," she told The Associated Press.
Police in Goteborg said in a statement they had evacuated the Roda Sten arts center, located beneath the city's landmark half-mile (933-meter) Alvsborg bridge, due to a threat deemed to pose "serious danger for life, health or substantial damage of property."
Goteborg police said they had assisted security police with the arrests, but declined to give any further comments.
Kvarnstrom declined to say if the arts center or the bridge were considered potential targets for a terror attack.
The Alvsborg bridge runs over Goteborg's harbor to connect the mainland with the island of Hisingen. The six-lane passage is a vital link from the Norwegian capital Oslo to southern Sweden.
Roda Sten is a former heating plant that was abandoned for years being reopened as an arts center in 2000, according to its website. About 400 people were celebrating the opening of an international biennial for contemporary art at the graffiti-covered brick building when police ordered everyone to leave, said Mia Christersdotter Norman, the head of Roda Sten.
"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 told The Associated Press.
"Police have searched the building but they didn't find anything," she said, adding the arts center 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.
Klas Eriksson, a disc jockey, was just about to start at Roda Sten when police broke up the party. People were worried but there was no panic, he said.
"It was just after midnight. Police said that they had arrested four people and that the building had to be evacuated," Eriksson told AP.
"I thought it was scary," he said. "Your thoughts go to 9/11, because it was just after midnight. But you don't know. It could be anything."
In December, suicide bomber Taimour Abdulwahab blew himself up in downtown Stockholm among panicked Christmas shoppers, injuring two people and 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. Vilks was not attending the art biennial in Goteborg.
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 radicalized Muslims in Sweden is primarily directed toward supporting militants in other countries, including Somalia, Afghanistan and Pakistan, it said.
Magnus Norell, a terrorism expert at the Swedish Defense Research Agency, declined to speculate about what was behind Sunday's arrests, but said the general threat in Sweden remains low.
"It was low in December 2010 as well -- but at the same time Sweden is a part of the world and a global context," he said.
Scandinavia has largely been focused on Islamic terrorism since Sept. 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.