OSLO, Norway — At least 80 people were killed in a shooting attack on a youth camp in Norway, police said early Saturday, a devastating elevation of the death toll in twin attacks that included a bomb attack in Oslo.

National police Chief Oystein Maeland said the attack had reached “catastrophic dimensions.”

Police arrested a 32-year-old Norwegian man at the youth camp on the island and linked him to both assaults but said they did not know the motive.

Norwegian media identified him as Anders Behring Breivik and said authorities searched his home.

At least seven people were killed Friday when the bomb exploded in the Norwegian capital in mid-afternoon, blowing out the windows of the prime minister’s building and damaging the finance and oil ministry building. Prime Minister Jens Stoltenberg was not in the building at the time. The blast scattered glass, shattered masonry and twisted steel across the streets.

A couple of hours later, a gunman opened fire at the youth camp on Utoya island, about 25 miles northwest of Oslo. After early reports of nine deaths, Norwegian police reported early Saturday that many more bodies had been found.

“The updated knowledge we are sitting on now is at least 80,” Maeland told a news conference. “We can’t guarantee that won’t increase somewhat,” he said, adding some victims were badly injured.

It was the biggest attack in Western Europe since the 2004 Madrid train bombings killed 191.

“You will not destroy us,” Stoltenberg, who had been scheduled to appear at an event on the island, said at an emotional press conference. “You will not destroy our democracy or our ideals for a better world.”

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