Bomb blast rocks Norway capital

A large bomb blast has hit near government headquarters in the Norwegian capital Oslo, killing at least one person.

The offices of Norwegian Prime Minister Jens Stoltenberg were damaged extensively - a government spokeswoman said he was safe.

Police said a number of people were injured in the city centre explosion.

No-one has said they were behind the attack, which witnesses said could be heard across the capital.

Television footage from the scene showed rubble and glass from shattered windows in the streets - smoke was rising from some buildings. The wreckage of at least one car was on one street.

All roads into the city centre have been closed, said national broadcaster NRK, and security officials evacuated people from the area, fearing another blast.

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

Oistein Mjarum, head of communications for the Norwegian Red Cross, said his offices were close to the site of the explosion