Norway paid tribute Friday to those killed and wounded in two terror attacks a week ago with a somber memorial service in Oslo organized by the youth movement of the ruling Labour Party.

As the service began, Prime Minister Jens Stoltenberg recalled the scores of young people lost to a “cold-blooded massacre.”

Police raised the death toll from 76 to 77 Friday after one of the wounded died.

The shooter targeted the party’s youth camp on Utoya Island, where it was holding a summer camp, after a bombing in downtown Oslo that struck government offices.

“The shots hit our young people, but they actually hurt the whole nation,” Stoltenberg told relatives of the victims and political leaders attending the service. “It was a vicious attack on all our common values.”

The prime minister urged young Norwegians not to feel alone as they struggled to come to terms with what happened, saying the party would support them.

“Out of our grief a much stronger unity will arise,” he said. “We are going to honor and celebrate our heroes — but most of all we are going stay true to our ideas and our values.”

Workers’ Youth League leader Eskil Pedersen, who was on Utoya during the shootings, vowed that the youth movement would return to the island where it has held political summer camps every year for decades.

“Today, we promise that July 22 next year we will be back at Utoya,” he said. “We will forever be the generation of July 22. That is a great responsibility,” he added. “This is a watershed, a new start and beginning of something lasting and important.”

The first funerals for victims of the attacks were also to take place Friday, for Bano Rashid, 18, and Ismail Haji Ahmed, 19.

Rashid, who was to be laid to rest in a Christian and Muslim ceremony, was reported to be a Kurd who came to Norway with her family in 1996 after fleeing Iraq.

Flags on government buildings were to fly at half staff Friday as a mark of respect.

Meanwhile, Anders Behring Breivik, the suspect, was interrogated for a second time Friday, police said.

Investigators had interviewed him a day after the attacks, but had more questions, police attorney Pal-Frederick Hjort Kraby said.

Breivik is being kept in solitary confinement at Ila Prison, near Oslo, which held Nazi prisoners during World War II. His sole contacts are with his lawyer and prison staffers who take food to him, Kraby said.

Breivik has admitted carrying out the bombing in Oslo, in which eight people died, and the shootings on Utoya, his lawyer and a judge have said. He has also pleaded not guilty.

Police said Thursday that the search in the water around the island was ongoing.

More than 50 investigators remained on the island and will likely remain there for several more weeks, officials said.

On Friday, authorities completed the identification of the dead, releasing the names of all 77.

A key question for investigators is whether Breivik acted alone.

“At this moment in time, we don’t think there are more people involved in this action, and we don’t know whether there are more bombs,” said Janne Kristiansen, director of the Norwegian intelligence police.

But she downplayed the possibility of further carnage.

“We think, more than likely, he has been on his own and nothing is going to happen here,” she said. “So people should go on living their lives.”

She said Breivik acted lawfully during his preparations, registering his weapons and used his farm as a front to collect the fertilizer that powered the bomb. His meticulousness extended to his communications with others, even in his Internet messages, which were “very moderate,” she said.

“He has been what we call a lone wolf,” she added. “With a lone wolf, they always operate alone, having no accomplices anywhere, and this is, obviously, what he has done.”

But, she added, “We believe that he might have had contacts in the rest of the world and we’re investigating this.”

His primary goal: “The focus from the world press, which he now has,” Kristiansen said. “He’s totally evil, and he’s using us, and he’s using you — especially the media — to bring forward his voice.”

Police predicted that most of the court hearings attended by Breivik will be closed to the public.

CNN’s Laura Smith-Spark and Nic Robertson contributed to this report.