STOCKHOLM - Swedish police arrested four people in Gothenburg, second largest city in Sweden, early Sunday morning suspected of plotting terrorist crime, according to a report from Swedish News Agency TT.

"I can confirm that the arrest was made with the help of the National Task Force and Gothenburg's police force," said Sara Kvarnstrom, Press Officer of the Swedish Security Services, SAPO, to TT.

"There's an ongoing judgment made, and it can always be changed. But right now we've judged that there is no reason to take security-raising measures in Swedish society in general," Kvarnstrom said.

Sweden's terror threat level has been raised to level three since last October, two months before the Stockholm terrorist bombing in December which wounded two people.

The arrest took place near Red Stone Concert Hall, an art gallery near the Alvsborg Bridge and the area has been evacuated and cordoned off.

The arrest time fell exactly on the tenth anniversary of the September 11 terrorist attacks in New York.