'Horrendous' explosion flattens homes

A large blast, thought to be a gas explosion, has destroyed several homes in Baltimore, Maryland.

One woman was killed, several other people seriously injured and at least three houses were completely levelled.

The blast, which also shattered windows in other homes, took place about 10am local time Monday.

Footage on local TV and social media showed a scene of devastation, with rubble strewn about the neighbourhood.

The Baltimore firefighters union, IAFF Local 734, posted on Twitter three people in a critical condition had been rescued.

"Several houses exploded. At least five people trapped, some children. A Collapse Response and Second Alarm has been called," the tweet said.

Army veteran Major Watkins witnessed the explosion and told the Baltimore Sun it "sounded like Korea (the Korean War).

"This was a very intense explosion," fire chief Niles Ford told a news briefing.

"This is a horrendous type situation that we're dealing with at this point".

Chief Ford said the cause of the gas explosion was under investigation.

"We are closely monitoring the situation in northwest Baltimore following this morning's horrific explosion," Maryland Gov. Larry Hogan said on Twitter.

"We have reached out to offer our full support to the ongoing response and recovery efforts, and are deeply grateful to the first responders on the scene."

Originally published as Major explosion destroys several homes