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 Norwegian public broadcaster NRK reported that at least one person was killed and several more injured, but a spokeswoman for the prime minister, Jens Stoltenberg, said he was “safe and not hurt.”
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SCANPIX, via Associated Press
A loud explosion shattered windows Friday at the government headquarters in Oslo which includes the prime minister’s office, injuring several people. Prime Minister Jens Stoltenberg is safe, government spokeswoman Camilla Ryste told The Associated Press
Stunned office staff and civil servants working in the vicinity of the bombed building said at least two explosions could be heard in close succession, as the sound of the blasts echoed across the city. Giant clouds of light-colored smoke continued to rise 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 that the initial blast occurred at around 3:20 p.m. local time. “We think there was more than one blast,” said Runar Kvernen, spokesman for the National Police Directorate under the Ministry of Justice and Police. Mr. Kvernen said he could not confirm the number of casualties; news reports said at least one or two people had been killed.

The cause of the explosions was not immediately clear, but a Reuters reporter described seeing the mangled wreckage of a car near one of the buildings.Photos and television footage showed windows blown out 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 center of the city, Norway’s capital, was sealed off, and police said they were on heightened alert as they combed through the debris in search of clues.

The explosions, which ripped through the cluster of modern office buildings around the Einar Gerhardsens plaza, occured at a time when many Norwegians were on vacation and many more had left their offices early for the weekend.

The office of Prime Minister Jens Stoltenberg is on the 16th floor of the most imposing government building in Oslo, a rectangular block that towers over the other buildings in the area. 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, 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.

While Norway has seen little political violence in recent years, the country is a member of NATO alliance and has a small fighting contingent in Afghanistan. It was one of several countries cited by Ayman al-Zawahri, the Al Qaeda leader, as potential targets for attack. In 2006, Norwegian newspapers reprinted Danish cartoons that angered Muslims by lampooning the Prophet 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.

A Norwegian security analyst, who asked not to be named, said the country has historically been seen as at low risk from terrorism, but cautioned that the nature of the explosion was still not known.

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.

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.”