President Barack Obama said Friday that a lethal bomb blast in Norway's capital of Oslo is a reminder that the world has a stake in stopping acts of terrorism.
The president also extended his condolences to Norway's people.
Addressing reporters after an Oval Office meeting with New Zealand's prime minister, Obama said he remembered how warmly Norwegians treated him when he traveled to Oslo to accept the Nobel Peace Prize in 2009.
He said "our hearts" go out to the Norwegian people. He also offered U.S. assistance with the investigation.
"It's a reminder that the entire international community has a stake in preventing this kind of terror from occurring," Obama said.
Secretary of State Hillary Rodham Clinton also offered words of support and sympathy while attending a meeting of Southeast Asian nations gathering in Indonesia.
"We stand with the people of Norway in this moment of sorrow and offer our deepest sympathies to the families and loved ones of those injured and killed," Clinton said.
"We remain ready to support the Norwegian government as it seeks to bring the perpetrators of this violence to justice," she said.
Norwegian authorities say the blast ripped open buildings, including the prime minister's office, and was followed by a shooting at a youth camp that left scores dead.
It was the peaceful nation's worst violence since World War II.
Norwegian Prime Minister Jens Stoltenberg was working at home at the time.
Later Friday, a man dressed as a police officer opened fire at the youth camp near the capital. Police had a suspect in custody in the shootings and say the incidents are linked.