UPDATE 2045 GMT: As Prime Minister Jens Stoltenberg delivers a message to the nation --- "You are not going to destroy us, you are not going to destroy our democracy" --- the Norwegian Minister of Justice says the shooter in the Utoeya attack is Norwegian.
UPDATE 1945 GMT: Police are now saying "9 or 10" people were killed in the Oslo explosion, caused by a car bomb outside the Prime Minister's office building.
UPDATE 1935 GMT: Alexandra Sandels of the Los Angeles Times passes on the first-hand observations of Swedish colleague Mattias Carlsson from the Utoeya shootings: "Between 15-20 bodies in water. Many young women. Groups of dead bodies at 4 different spots around the island. 8 people dead in one spot, 5-6 in another."
UPDATE 1930 GMT: Police now say at least seven people died in the explosion in central Oslo. Two have been seriously injured.
The casualty total at the Utoeya shootings is still unknown. A Norwegian journalist on the scene reports, "Ambulances on docks close to lake surrounding Utøya. Paramedics still working to save lives/treat injured in front of our eyes."
UPDATE 1710 GMT: A gunman, disguised as a police officer, injured several people when he opened fire at a youth camp of the ruling Labour Party in Utoeya, an island 20 miles from Oslo.
No connection has been established yet with the bombing outside Prime Minister Jens Stoltenberg's office in Oslo. A former Prime Minister was reportedly at the youth meeting today, and there are reports that Stoltenberg was due at the event tomorrow.
A man has been arrested in the incident.
UPDATE 1520 GMT: Norwegian TV now says two people are dead. Oslo police have told the BBC that a bomb is the cause of the explosion.
UPDATE 1500 GMT: Norwegian broadcaster NRK has said one person has died from injuries suffered in the explosion.
A photograph from Demotix appears to show a dead body outside the building. br>
This afternoon, the Norwegian Prime Minister's Office was apparently targeted by a bomb, causing signficant damage to the building and others in the area.
Eight people are reportedly wounded. Prime Minister Jens Stoltenberg was uninjured.
All roads to Oslo city centre have been closed.