A source familiar with the incident said the three men on board the helicopter reported seeing a "flying saucer-shaped" object encircled by lights speeding toward them as they prepared to land, The Sun reported Friday.

"It closed in at great speed, aiming straight at the helicopter," the source said.

"The chopper had to swerve sharply to avoid being hit. The guys said if they'd stayed where they were, they'd be dead -- it would've been a direct hit. They are convinced it was a UFO. It sounds far-fetched, but they know what they saw," the source said. "They belted across the Bristol Channel in pursuit, but it was too quick. They got to the North Devon coast and had to turn back because they were running low on fuel."

The British Ministry of Defense, which typically investigates cases involving UFOs, said police have not informed it of the incident.

"We've heard nothing about this. But it is certainly not advisable for police helicopters to go chasing what they think are UFOs," a representative said.