Oslo – Powerful explosions shook central Oslo on Friday afternoon, blowing out the windows of several government buildings, including one housing the office of the Norwegian prime minister. The state television broadcaster, citing the police, said seven people were killed and at least 15 injured; a spokeswoman for the prime minister, Jens Stoltenberg, said he was “safe and not hurt.”
Shortly after the explosions, which appeared to be a bomb attack, a man dressed as a police officer opened fire on a summer camp for young members of the ruling Labor Party on the island of Utoya in the Oslo fjord, about 25 miles from the city, and wounded at least five, a Norwegian security official said.
“The situation’s gone from bad to worse,” said Runar Kvernen, spokesman for the National Police Directorate under the Ministry of Justice and Police, adding that most of the children at the camp were between 15 and 16 years-old. There were initial reports that Mr. Stoltenberg was scheduled to attend a meeting at the camp.
As fear spread through the capital, the police moved to lock down a wide area of the city center, where the streets were already nearly deserted.
The attacks appeared to be part of a coordinated assault on the ordinarily peaceful Scandinavian nation, as images of the damaged government buildings called to mind past terror attacks in Beirut or Baghdad or Oklahoma City.
Though the police did not immediately connect the explosions with terrorism, the mangled wreckage of a car could be seen in front of the main government building, flipped on its side, damaged so badly that its make and color were not apparent. A large area of the sidewalk pavement around it was completely blown away. Reports in local media said that officials were assuming it was a deliberate bombing.
A terror group, Ansar al-Jihad al-Alami, or the Helpers of the Global Jihad, issued a statement claiming responsibility for the attack, according to Will McCants, a terrorism analyst at C.N.A., a research institute that studies terrorism. The message said the attack was a response to Norwegian forces’ presence in Afghanistan and to unspecified insults to the Prophet Muhammad. “We have warned since the Stockholm raid of more operations,” the group said, according to Mr. McCants’ translation, apparently referring to a bombing in Sweden in December 2010. “What you see is only the beginning, and there is more to come.” The claim could not be confirmed.
Norway is a member of the NATO alliance and has a small fighting contingent in Afghanistan. It was one of several countries named by Ayman al-Zawahri, the leader of Al Qaeda, as potential targets for attack. In 2006, Norwegian newspapers reprinted Danish cartoons that angered Muslims by lampooning Muhammad. Norway has also historically been a frequent participant in peacekeeping missions and a host for diplomatic talks, including the 1993 Oslo Accords between Israel and the Palestinians. The Nobel Peace Prize is awarded by a committee of the Norwegian Parliament.
Muslim leaders in Norway swiftly condemned the attacks. “This is our homeland, this is my homeland; I condemn these attacks and the Islamic Council of Norway condemns these attacks, whoever is behind them,” said Mehtab Afsar, secretary general of the Islamic Council of Norway.
Norwegian news media, citing the police, said the shooting suspect at the camp had been arrested.
Witnesses on the island told Norwegian television that the man identified himself as a police officer when he entered the camp. “He said it was a routine check in connection with the terror attack in Oslo,” one witness told VG Nett, the Web site of a national newspaper.
Bjorn Jarle Roberg-Larsen, a Labour Party member who had telephone contact with teenagers on the island, said: “Kids have started to swim in a panic, and Utoya is far from the mainland. Others are hiding. Those I spoke with don’t want to talk more. They’re scared to death.”
In Oslo, stunned office workers and civil servants in the vicinity of the bombed buildings said that at least two explosions were heard in quick succession, as the sound of the blasts echoed across the city. Giant clouds of light-colored smoke rose hundreds of feet into the air over the city as a fire burned in one of the damaged structures, a six-story office building that houses the Oil Ministry.
The police said the initial explosion occurred at around 3:20 p.m. local time. “We think there was more than one blast,” Mr. Kvernen said. He said he could not confirm the number of casualties.
The force of the explosion blew out nearly every window in the 17-story office building across the street from the oil ministry, and the street and plaza areas on each side were strewn with glass and debris. The police said they were on heightened alert as they combed through the debris in search of clues.
“This is very serious,” Mr. Stoltenberg told the Norwegian broadcaster TV2 by telephone, but he said it was still too early to call the blast a terror attack.
At about the time of his television appearance, Norwegian media reported that the police had also sealed off the offices of the broadcaster after a suspicious package was discovered there.
The explosions, which ripped through the cluster of modern office buildings around the Einar Gerhardsens plaza, occurred at a time when many Norwegians were on vacation and many more had left their offices early for the weekend.
Mr. Stoltenberg’s office is on the 16th floor of the tallest building in the area, a towering rectangular block whose facade and lower floors were damaged by the explosions. The Justice Ministry also has its offices in the building.
Helge Skinnes, a spokesman for the prime minister’s office, was in the building at the time of the explosions and was still at the site when reached by telephone Friday afternoon. “We have a crisis situation,” Mr. Skinnes said, declining to comment further.
Norwegian authorities said they believed a number of tourists were in the central district and around the main government buildings at the time of the explosion, but that it was not otherwise crowded. “Luckily it’s very empty,” said Stale Sandberg, who works in the directorate for family, youth and children affairs, a few blocks down the street from the prime minister’s office.
At the site of the explosion, the police evacuated and roped off the area as tension mixed with shaken fascination. People milled around the area, some snapping photos of the destruction. Store windows were blown out for several blocks around.
Earlier this month, Norwegian prosecutors filed a terrorism charge against Mullah Krekar, the Iraqi-born founder of the Kurdish Islamist group Ansar al-Islam, who is accused of making death threats against the head of Norway’s Conservative Party, Erna Solberg. Mr. Krekar co-founded Ansar al-Islam in 2001, but said a year later that he no longer led the group, which is listed as a terrorist organization by the United States and United Nations.
Norwegian authorities have previously ordered his expulsion from the country, but the process was suspended amid concerns that he would face the death penalty in his home country.
A threat assessment released in March by the Norwegian police said that though support for extremist Islamic terrorism was not widespread, “activity in certain communities” meant that the threat level would be heightened in 2011. “Some extreme Islamists currently appear to be more globally oriented,” the report said, “and it is primarily this group who could present a direct threat to Norway in the year ahead.”
The report also added that Norwegian businesses and high-profile figures were likely to be targets. Three Norwegian men were arrested in July 2010 on suspicion of terrorism and were said to be a terrorist “node” in a larger global network, American counterterrorism officials said at the time.
After the explosions, the city filled with an unfamiliar sense of vulnerability Friday. “We heard two loud bangs and then we saw this yellow smoke coming from the government buildings,” said Jeppe Bucher, 18, who works on a ferry boat less than a mile from the bomb site. “There was construction around there, so we thought it was a building being torn down.”
He added, “Of course I’m scared, because Norway is such a neutral country.”
Elisa Mala reported from Oslo, and J. David Goodman from New York. Reporting was contributed by Souad Mekhennet, Ravi Somaiya and Matthew Saltmarsh from London, and Katrin Bennhold from Paris.
This article, “7 Dead in Oslo from Blasts and Gun Attack,” originally appeared in The New York Times.