WASHINGTON (AFP) - Searchers have recovered the remains of one of three occupants of a hot air balloon that went up in flames after hitting a power line in the US state of Virginia, police said on Saturday.

The two others were missing in the accident, which occurred on Friday night as the balloon was making its descent in a pre-designated field, said Ms Corrine Geller, spokesman for the Virginia state police.

"We spent all night searching for the wreckage of the basket, the balloon," she told a news conference. "It was just before midnight that we were able to locate one of the occupants."

"At this time, we are still searching for the two others that were in the balloon as well as the wreckage sites of the basket and the balloon itself," she said.

Searchers located a "debris site" where they found items that would have been in the balloon, she added.

Witnesses watched as the balloon caught fire in the evening sky after hitting a power line as it was coming down to earth, she said.

The pilot, who was seen struggling to manage the situation and extinguish the fire, opened up the top of the balloon so it would not rise with the heat.

"The witnesses heard an explosion and after that, the basket and the balloon actually separated," Ms Geller said.

The balloon was one of three that launched at 8pm on Friday local time from Meadow Event Park in Caroline County, Virginia. The other two landed before it without incident.