Five people were killed and two others injured when a house exploded on Thursday night in a borough about 40 miles north of Philadelphia, the authorities said.
The police and fire officials in Pottstown, Pa., were dispatched to the site just after 8 p.m., Justin M. Keller, the Pottstown borough manager, told reporters during a news conference on Thursday night. They found “multiple victims needing medical care,” he said.
The authorities initially confirmed four fatalities and two people hospitalized with injuries, but the death toll grew to five on Friday, Mr. Keller said at a second news conference.
One of the injured people was in critical but stable condition on Friday afternoon, and the other was undergoing surgery for unknown injuries at a hospital, he said.
Mr. Keller said that as of Friday afternoon and “based on preliminary information from the investigation,” officials believed that everyone had been accounted for.
The cause of the explosion was still unknown, officials said on Friday. They declined to disclose the identities of those killed or injured, saying they needed to notify relatives.
An investigation was underway, Mr. Keller said, and multiple agencies, including the Pennsylvania State Police and the Red Cross, had sent personnel to the site late Thursday night. A Philadelphia arson and explosive team was also on the scene to assist with the investigation.
“This is still an active emergency scene,” Mr. Keller said, adding that residents of Pottstown, a borough of about 22,000 residents, should avoid the area of the explosion.
Video and images from local news outlets showed pieces of wood and other debris scattered at the site of the home and strewn across the street.
Stephen J. Rodriguez, the superintendent of the Pottstown School District, said in a message to parents on Thursday night that classes would be canceled on Friday because of the explosion.