With the recent anniversary of Sept. 11, officials all over the world have had their guard up regarding the possibility of a terrorist attack. And on Sunday, four people were arrested in Sweden on suspicion of planning acts of terrorism in Goteborg.

The Swedish Security Service along with the National Task Force arrested four men who posed a “human life threat” to people in the Roda Sten Art Center.

About 400 people were at the art center on Sunday celebrating the Goteborg International Biennial for Contemporary Art when the director of the art center, Mia Christersdotter Norman, received a phone call saying that everyone should evacuate from the building.

The specifics of the nature of the threat or the possible plan of attack was not given since the case is still ongoing, and prosecutors have three days to charge the men.

The timing close to Sept. 11 cannot be completely ruled out as just a coincidence and it is unknown if the attack was Al Qaeda-related or if it has anything to do with the recent attack in Norway leaving 77 dead.

Sweden was the target this past December when a suicide bomber killed himself and left two wounded in the Stockholm city center.