OSLO, Norway -- Norwegian Prime Minister Jens Stoltenberg on Monday marked the second anniversary of the terror acts that killed 77 people by calling for a continued fight against all forms of extremism.

In a wreath-laying ceremony at the government headquarters, Stoltenberg said society has to stand up against "populist right-wing parties" that are on the rise in Europe, and extremist Islamists who continue to send out threats.

"No extremist shall scare us from moving freely, thinking freely or speaking freely," Stoltenberg said. "Our values are our strongest weapon and our strongest protection against violence and terror."

Far-right fanatic Anders Behring Breivik has confessed to the July 22, 2011, attacks in which he killed eight people in a bombing at the government headquarters and 69 others in a shooting spree at the left-wing Labor Party's youth camp on Utoya island.

In 2012, he received a 21-year prison sentence that can be extended for as long as he's considered dangerous to society. Legal experts say that likely means he will be locked up for life.

Later Monday, an emotional ceremony was held on the shores opposite Utoya island.

"Today our thoughts are especially with all parents, siblings, partners and families who lost what was dearest to them," said Eskil Pedersen, the head of the Labor Party's youth chapter and a survivor of the massacre.

He said many survivors and relatives are still struggling with their daily lives.

"There are still many who are burdened with grief, who struggle to concentrate in school or at work, who see that Norway has moved on, but who don't feel they have the power to do the same," he said. "My hope is that this community has room for everyone who was marked for life on July 22. Let us be there for each other, even if July 22 is no longer talked about on a daily basis."