A house exploded as police were investigating reports of gunshots being fired from the property by a man.
Footage of the blast in the US showed a huge fireball shoot up into the air as the entire home went up in flames and collapsed, spraying debris all around.
Witnesses said the explosion shook nearby buildings and that they could hear it from miles away.
Officers had gone to the address in Arlington, Virginia, at about 4.45pm on Monday after neighbours said they heard the sound of a weapon being fired.
They later determined the shots came from a flare gun, Arlington County police spokesperson Ashley Savage told reporters.
As officers tried to serve a search warrant at the home, “the suspect inside the residence discharged several rounds”, she said.
“The house subsequently exploded.”
It happened at around 8.25pm as officers were trying to make contact with the person inside – who has not been named by police.
Officials have not been able to go into the home and could not confirm whether there were any deaths. The suspect was inside when the explosion occurred, Ms Savage said.
“At this point, we’re only aware of one individual who was inside the home,” she added.
Some police officers suffered minor injuries and no one needed to be taken to hospital.
Carla Rodriguez, of South Arlington, said she could hear the explosion more than two miles away.
“I actually thought a plane exploded,” she said.
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Bob Maynes thought maybe a tree had fallen on his house when he heard the explosion.
“I was sitting in my living room watching television and the whole house shook,” he said.
“It wasn’t an earthquake kind of tremor, but the whole house shook.”
The cause of the blast is being investigated, Arlington Fire Department officials said.
FBI agents and federal fire investigators are at the scene and assisting in the investigation, the Bureau of Alcohol, Tobacco, Firearms and Explosives said.
The blaze was under control by 10.40pm.
