Bomb blast rocks Oslo government buildings

A powerful bomb blast rocked government and media buildings in Norway's capital Oslo on Friday, causing "deaths and injuries" and dealing heavy damage, police said.

Police said a bomb was behind the explosion and Norwegian media reported that at least two people died.

"A powerful explosion has taken place in the government quarter," Norwegian police said in a statement.

"Police can confirm there were deaths and injuries following the explosion in the government quarter this afternoon," police added later.

Images on Norwegian television showed the prime minister's office and other buildings heavily damaged, sidewalks covered in broken glass and smoke rising from the area.

Prime Minister Jens Stoltenberg was reported to have not been in his office at the time of the blast.

Police had sealed off the area, which houses the offices of the prime minister, the finance ministry and the country's biggest tabloid newspaper Verdens Gang (VG).

Two cabinet ministers told AFP that Stoltenberg had been scheduled to be visiting areas far outside Oslo on Friday.

News agency NTB also reported that Stoltenberg was "safe".

Witnesses said the damage was extensive and that injured victims could be seen.

"I see that some windows of the VG building and the government headquarters have been broken. Some people covered with blood are lying in the street," a journalist with public radio NRK said from the scene.

"There is glass everywhere. It is total chaos. The windows of all the surrounding buildings have been blown out," said NRK journalist Ingunn Andersen.

The radio reported that the explosion seemed to happen near the finance ministry, which is near the Norwegian prime minister's office and the VG editorial offices.

Photos posted on the NRK website also showed shattered glass in front of the devastated facade of the VG building, soldiers closing off the area and people surrounding someone apparently injured in the blast.

It was not immediately known who was behind the bombing, but Norway's intelligence police agency (PST) said in February that Islamic extremism was a major threat to the country.

Islamic extremism is "our main priority and our main concern," PST chief Janne Kristiansen said at the time, while presenting the agency's annual risk assessment report.

The report said: "Although few people in Norway support Islamic extremism, there are activities within some groups that could contribute to heightening the security risk in 2011."

NATO member Norway, which counts some 500 troops in Afghanistan, has never suffered an attack at home by Islamic extremists.

However, police last year arrested three Muslim men based in Norway suspected of planning an attack using explosives in the Scandinavian country.

Norwegian prosecutors earlier this month also filed a terrorism charge against Mullah Krekar, founder of the Kurdish Islamist group Ansar al-Islam, who was accused of threatening a politician with death over his potential deportation from the country.

Krekar had warned that "Norway will pay a heavy price" if he were deported.

Norwegian F-16 fighter jets are also participating in air strikes in Libya, though the country has said it will withdraw its forces from the Libya operations on August 1.

The Norwegian military said in May that it had been the victim of a serious cyber attack at the end of March on the day after its jets for the first time carried out bombings in Libya.

Neighbouring Sweden was targeted in a suicide bombing last December when Taimour Abdulwahab, a 29-year-old whose family fled from Iraq to Sweden in 1991, blew up himself and his car in a deserted side-street off of Stockholm's busiest pedestrian thoroughfare, injuring two people.