An Amtrak train carrying nearly 140 passengers was evacuated near Denver after a passenger threatened the crew and others onboard, claiming he had a weapon and bomb, an Amtrak spokeswoman said early Monday.

Police met the California Zephyr train about 22 miles west of Denver late Sunday after the crew alerted authorities about the unidentified passenger's threats, Amtrak spokeswoman Karina Romero said.

Authorities detained the man for questioning and did a sweep of the baggage car and the passenger car where he was sitting. The man was carrying a knife, and a bomb-sniffing dog focused on his bag, Romero said.

"There was something that was in that bag that made the dog stop," Romero said, declining to elaborate.

No injuries were reported.

Passengers were evacuated and transported by bus back to Denver, Romero said.

The California Zephyr leaves each day from Emeryville, Calif. to Chicago.