he suspect is reported by local media to have had links with right-wing extremists. Police named him as Anders Behring Breivik. His Oslo apartment was searched overnight.

The BBC's Richard Galpin, near the island, says that Norway has had problems with neo-Nazi groups in the past but the assumption was that such groups had been largely eliminated and did not pose a significant threat.

Police say they are investigating whether the attacks were the work of one man or whether he had help.

"At Utoeya, the water is still being searched for more victims," deputy police chief Roger Andresen told reporters.

"We have no more information than... what has been found on [his] own websites, which is that it goes towards the right and that it is, so to speak, Christian fundamentalist."

"He asked people to gather round and then he started shooting, so these young people fled into the bushes and woods and some even swam off the island to get to safety."

One 15-year-old eyewitness described how she saw what she thought was a police officer open fire.

"He first shot people on the island. Afterward he started shooting people in the water," youth camp delegate Elise told AP.

Mr Stoltenberg had been due to visit the camp on Saturday. Foreign Minister Jonas Gahr Store, who visited the camp on Thursday, praised those who were attending.

"The country has no finer youth than young people who go for a summer camp doing politics, doing discussions, doing training, doing football, and then they experience this absolutely horrendous act of violence," he said.