At least 87 people died when a gunman opened fire at an island youth camp in Norway, hours after a bomb attack on the capital, Oslo, police say.
Oslo police are questioning a 32-year-old Norwegian man in connection with both attacks.
The man was arrested on tiny Utoeya island outside Oslo, where police say he opened fire on teenagers.
Earlier, the number of dead from the Utoeya shooting spree, which is among the world’s most deadly, was put at 10.
The earlier bomb attack killed at least seven people. Prime Minister Jens Stoltenberg, whose Oslo offices were among those badly hit by the blast, described the attacks as “bloody and cowardly”.
The attacks are the worst Norway has seen since World War II. Hundreds of young people were attending the summer camp organised by the ruling Labour Party on Utoeya island.
Eyewitnesses described how a tall, blonde man dressed as a policeman opened fire indiscriminately. People said that after the gunman started shooting, campers jumped into the water to try to escape the hail of bullets.
Police say they discovered many more victims after searching the area around the island.
“It goes without saying that this gives dimensions to this incident that are exceptional,” police director Oystein Maeland is quoted as saying by the Associated Press news agency.
Police say many others are injured, and warned the number of dead may rise further as rescue teams continued to scour the waters around the island. Some of the teenagers were shot at as they tried to swim to safety.
The gunman is reported to have been armed with a handgun, an automatic weapon and a shotgun.
There are also concerns that more victims may still be inside buildings hit by the initial massive explosion in Oslo.
Emergency services have had difficulty accessing these buildings amid concerns about further possible explosions as well as fears the blast may have left buildings unstable.
The BBC’s Richard Galpin, north of Oslo, says that the attacks have been a huge shock for people: Norway has never experienced anything like this in the past and the violence of the past day has left people totally stunned.