Authorities in Oslo are now confirming that the blast that rocked the prime minister's offices in central Oslo was in fact a bomb.

Two are reported killed and several more injured. Seven are being treated at Oslo University Hospital, according to spokesman Jo Heldaas.  Norwegian Prime Minister Jens Stoltenberg is safe and unharmed.

Stoltenberg told local station NRK by phone, This is a very serious situation. All available emergency personnel are at the scene and my thoughts go to those who have been hit by it [the attack].

The government's crisis advice committee is now gathered to decide the next course of action, and Minister of Justice, Knut Storberget, Health Minister Anne-Grete Strøm-Erichsen, and Jonas Gahr Støre, are now on their way to a meeting. PM Stoltenberg says he is in continuous contact with Minister of Defence Grete Faremo.

The blast was reported at 3:26 p.m. local time.  Officers at today's press conference from Grønland police station say they received no advance warnings. The terror threat level has now been increased.

There have been one or two powerful explosions in the government quarter in Oslo, police said in a statement. Police are urging people to stay away from the center of the city and limit their use of mobile phones.

Today's bombing marks the first time that the Norwegian capital has encountered such an attack, however, local police did arrest three terrorist suspects last year with possible ties to al-Qaeda.