US President Barack Obama offered condolences to Norway after deadly twin attacks and urged countries around the world to step up cooperation to combat terror.
Speaking during a meeting with New Zealand's Prime Minister John Key, Obama called the attacks "a reminder that the entire international community has a stake in preventing this kind of terror from occurring."
"We have to work cooperatively together on intelligence and in terms of prevention of these kinds of horrible attacks," the president said.
Obama, who visited Oslo in 2009 to receive the Nobel Peace Prize, fondly recalled his welcome in the NATO ally and said he "wanted to personally extend my condolences to the people of Norway."
"Our hearts go out to them and we will provide any support we can to them," said Obama, who earlier received a briefing on the attacks from his top anti-terrorism adviser John Brennan.
A blast tore through government buildings and a gunman opened fire at a youth meeting of the ruling party, leaving at least 80 people reported dead.
US Secretary of State Hillary Clinton said the United States "strongly condemns today's attacks in Oslo and Utoya Island.
"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," said Clinton.
State Department spokeswoman Heide Bronke Fulton called the attacks "despicable" and said the embassy in Oslo has urged all US citizens to avoid the center of the Norwegian capital.
"The US has reached out to the Norwegian authorities to offer assistance, but there have been no specific requests from the Norwegians thus far," Fulton told AFP.
New Zealand's prime minister, in his meeting with Obama, also voiced his "sympathies and concerns" over the attacks in Norway.
"If it is an act of global terrorism, then I think that what it shows is no country, large or small, is immune from that risk," Key said.
"And that's why New Zealand plays its part in Afghanistan as we try and join others like the United States in making the world a safer place," he said.
New Zealand has sent 70 elite special force troops and 140 reconstruction personnel to Afghanistan.