WASHINGTON (AFP) - An inmate who went on the run from a Kentucky prison begged to be let back in just a day later because he was so cold, US police said.

Robert Vick escaped from the Blackburn jail on Sunday but turned up at the Sunset Motel in Lexington the next day asking for the police to be called, Ms Sherelle Roberts, a Lexington police spokeswoman, told AFP.

Vick said he wanted to go back to prison because he was so cold, added the spokeswoman, saying temperatures in the central-eastern state were -20 degrees Celsius.

The 42-year-old was placed under observation for a few hours "because of exposure to the cold" and then returned to the Blackburn jail. The US is in the grip of a blast of bone-chilling cold that has snarled air travel, closed schools and prompted calls for people to stay inside, as temperatures plunged to lows not seen in two decades.