A U.S. drone crashed Saturday in Pakistan's tribal region, U.S. and Pakistani officials said.

The cause of the crash was unknown, but a U.S. official denied reports that the drone had been shot down.

Two Pakistani intelligence officials told CNN that witnesses in North Waziristan reported the crash near the village of Machikhel. The Pakistanis had only these witness accounts to go by, and were working to verify the crash and its causes with its own sources, the officials said.