OSLO, Norway (AP) -- A Norwegian who dressed as a police officer to gun down summer campers killed at least 80 people at an island retreat, horrified police said early Saturday. It took investigators several hours to begin the realize the full scope of Friday's massacre, which followed an explosion in nearby Oslo that killed seven and that police say was set off by the same suspect.
The mass shootings are among the worst in history. With the blast outside the prime minister's office, they formed the deadliest day of terror in Western Europe since the 2004 Madrid train bombings killed 191.
Police initially said about 10 were killed at the forested camp on the island of Utoya, but some survivors said they thought the toll was much higher. Police director Oystein Maeland told reporters early Saturday they had discovered many more victims.
"It's taken time to search the area. What we know now is that we can say that there are at least 80 killed at Utoya," Maeland said. "It goes without saying that this gives dimensions to this incident that are exceptional."
Maeland said the death toll could rise even more. He said others were severely injured, but police didn't know how many were hurt.
A suspect in the shootings and the Oslo explosion was arrested. Though police did not release his name, Norwegian national broadcaster NRK identified him as 32-year-old Anders Behring Breivik and said police searched his Oslo apartment overnight. NRK and other Norwegian media posted pictures of the blond, blue-eyed Norwegian.
A police official said the suspect appears to have acted alone in both attacks, and that "it seems like that this is not linked to any international terrorist organizations at all." The official spoke on condition of anonymity because that information had not been officially released by Norway's police.
"It seems it's not Islamic-terror related," the official said. "This seems like a madman's work."
The official said the attack "is probably more Norway's Oklahoma City than it is Norway's World Trade Center." Domestic terrorists carried out the 1995 attack on a federal building in Oklahoma City, while foreign terrorists were responsible for the Sept. 11, 2001 attacks.
The official added, however, "it's still just hours since the incident happened. And the investigation is going on with all available resources."
The motive was unknown, but both attacks were in areas connected to the ruling Labor Party government. The youth camp, about 20 miles (35 kilometers) northwest of Oslo, is organized by the party's youth wing, and the prime minister had been scheduled to speak there Saturday.
A 15-year-old camper named Elise said she heard gunshots, but then saw a police officer and thought she was safe. Then he started shooting people right before her eyes.
"I saw many dead people," said Elise, whose father, Vidar Myhre, didn't want her to disclose her last name. "He first shot people on the island. Afterward he started shooting people in the water."
Elise said she hid behind the same rock that the killer was standing on. "I could hear his breathing from the top of the rock," she said.
She said it was impossible to say how many minutes passed while she was waiting for him to stop.
At a hotel in the village of Sundvollen, where survivors of the shooting were taken, 21-year-old Dana Berzingi wore pants stained with blood. He said the fake police officer ordered people to come closer, then pulled weapons and ammunition from a bag and started shooting.
Several victims "had pretended as if they were dead to survive," Berzingi said. But after shooting the victims with one gun, the gunman shot them again in the head with a shotgun, he said.
"I lost several friends," said Berzingi, who used the cell phone of one of those friends to call police.
The blast in Oslo, Norway's capital and the city where the Nobel Peace Prize is awarded, left a square covered in twisted metal, shattered glass and documents expelled from surrounding buildings. Most of the windows in the 20-floor high-rise where Prime Minister Jens Stoltenberg and his administration work were shattered. Other buildings damaged house government offices and the headquarters of some of Norway's leading newspapers.
The dust-fogged scene after the blast reminded one visitor from New York of Sept. 11.
Ian Dutton, who was in a nearby hotel, said people "just covered in rubble" were walking through "a fog of debris."
"It wasn't any sort of a panic," he said, "It was really just people in disbelief and shock, especially in a such as safe and open country as Norway. You don't even think something like that is possible."
Police said the Oslo explosion was caused by "one or more" bombs.
The police official who spoke on condition of anonymity said the Oslo bombing occurred at 3:26 p.m. local time (1:26 p.m. GMT), and the camp shootings began one to two hours later. The official said the gunman used both automatic weapons and handguns, and that there was at least one unexploded device