OSLO, Norway — A Norwegian government official says there are people trapped in the buildings hit by a bomb blast today at the government headquarters in Oslo.

State Secretary Kristian Amundsen told BBC that “there are still people in the buildings” at the blast site. He declined to elaborate, saying: “I can’t go into details.”

He said this situation is the worst his country has seen.

The powerful bomb tore open several Oslo buildings, including the prime minister’s office, killing at least one person.

Prime Minister Jens Stoltenberg is safe, government spokeswoman Camilla Ryste said. A senior adviser to the prime minister, Oivind Ostang, said Stoltenberg was working at home today and was not in the building.

She said the cause of the explosion was not clear. Asked whether police suspected a terror attack, she said: “It’s too early to speculate in that.”

NRK showed video of a blackened car lying on its side amid the debris.

Most of the windows in the 20-floor high-rise were blown out, and the bottom floor appeared to be gutted. Nearby offices were also heavily damaged and evacuated, including those housing some of Norway’s leading newspapers and news agency NTB.

By The Associated Press