A man was seriously injured after an explosion at a home that is under construction in Manassas, Va., authorities said.

It was not immediately known what caused the explosion just before 7 a.m. Tuesday in the 11600 block of Kahns Road, fire officials said. The cause is under investigation, according to Matt Smolsky, a spokesman for the Prince William County Fire Department.

Smolsky said the man was airlifted to the burn center at Washington Hospital Center. He also said it was not clear what had exploded at the site.