(Reuters) - A Pennsylvania house fire that killed two children has triggered a federal safety investigation after local officials said it was caused by a malfunctioning hoverboard, believed to be the first fatal blaze in the United States caused by one of the devices.

Two girls were killed in Harrisburg on March 10 in a fire that the local fire department said it had traced to a battery-operated hoverboard that was charging.

Hoverboards - two-wheeled transportation devices - are generally powered by lithium-ion batteries.

Numerous reports of fires caused by overheated battery packs forced more than a half-million of the boards to be recalled last year.

The U.S. Consumer Product Safety Commission, which has investigated 60 hoverboard fires since 2015, has not yet determined the brand and model of the hoverboard involved in the Harrisburg blaze, spokeswoman Patty Davis said.

“We want to know whether the hoverboard was a previously recalled model or a different model that would need further analysis,” said Ann Marie Buerkle, the commission’s acting chairman.

The commission is not aware of any other hoverboard-linked blaze that has resulted in a death, Davis said.

The fire started on the second story of a residential building of the state capital while several children inside, firefighters said. Ashanti Hughes, 2, and Savannah Dominick, 10, died.

Lieutenant Dennis DeVoe, a 21-year fire department veteran, was killed in a car accident while en route to the blaze, firefighters said.