A powerful blast tore open several Oslo buildings including the prime minister''s office on Friday. Two people were reportedly killed and several were injured, as the blast shattered windows and coated the street with documents.

Prime Minister Jens Stoltenberg is safe, government spokeswoman Camilla Ryste told The Associated Press, although it was unclear whether that meant he was uninjured. Norway''s public broadcaster, NRK, said one person was confirmed killed.

There was no immediate word on the cause of the blast. NRK showed video of a blackened car lying on its side amid the debris.

Most of the windows in the 20-floor highrise were blown out, and the bottom floor appeared to be gutted. Nearby offices were also heavily damaged and evacuated, including those housing some of Norway''s leading newspapers and news agency NTB.

An AP reporter who was in the NTB office said the building shook from the blast and all employees evacuated as the alarm went off. Down in the street, he saw one person with a bleeding leg being led away from the area.

The government building houses the offices of the prime minister and his administration. Several ministries are in surrounding buildings.

The blast comes as Norway grapples with a homegrown terror plot linked to al-Qaida. Two suspects are in jail awaiting charges.

Last week, a Norwegian prosecutor filed terror charges against an Iraqi-born cleric for threatening Norwegian politicians with death if he is deported from the Scandinavian country. The indictment centered on statements that Mullah Krekar - the founder of the Kurdish Islamist group Ansar al-Islam - made to various news media, including American network NBC.

Terrorism has also been a concern in neighboring Denmark since an uproar over cartoons of the Prophet Muhammad six years ago. Danish authorities say they have foiled several terror plots linked to the 2005 newspaper cartoons that triggered protests in Muslim countries. Last month, a Danish appeals court on Wednesday sentenced a Somali man to 10 years in prison for breaking into the home of the cartoonist.