The son of a Belfast man narrowly avoided being on Utoya island when Anders Behring Breivik carried out his shooting spree.
Breandan Meyn Whyte (15), whose father Eddie is originally from Belfast, planned to go to the youth camp with friends until his family decided to take a holiday in Ireland instead.
Right-wing extremist Breivik ran amok at the summer camp minutes after detonating a massive bomb in Oslo which killed seven people.
Last night Breandan spoke of his lucky escape.
He said: "I would definitely be at the camp since me and my friends were planning on going but it was cancelled when we decided to go to Ireland."
The young Norwegian spoke of his shock at hearing people he knew had been gunned down on the island.
He said: "I know a couple of people who were out there. I know the leader who was shot and is dead now.
"The leader from my section had to swim from the island to escape and he survived. No one from our area is dead, but there are some missing."
Breandan said that there were emotional scenes as he and friends contacted each other after the attack: "One of my friends was nearly in tears as he didn't know if I had left for camp or not. I'm glad I'm here instead, thank God for that, but I can't believe what happened."
The teenager's father Eddie has lived in Norway for 23 years and is currently on holiday with his family in Donegal.
He said: "We've lost friends, there are still five young people missing from our area, presumed dead. It's a shock. It's hard to handle. We discussed how much information we wanted to know because it is pretty brutal. In a way it's maybe a blessing that we were here, that we didn't get to see everything, because it's horrific."
"My son Breandan would've been at the camp if we hadn't been on holiday. Actually he was quite annoyed he couldn't go to the camp," said Mr Whyte.
The former Belfast man said the support from people in his home city for victims of the attack was important.
He said: "We have our own experiences from Ireland; but didn't expect it to happen in Norway.
"Norway is a small country with five million people, just like Ireland. Oslo is like Belfast, with hills, trees, seaside and quite a lot of Irish people. I don't think there's a single part of the country that isn't grieving."