John Foreman, 32, who has links to Burnley, absconded from HMP Kirkham on Sunday (May 30).
A coordinated search for him is ongoing and detectives are urging the public to remain vigilant and report any immediate sightings to 999.
The 32-year-old is described as 5ft 11ins, of a slight build, with cropped brown hair and blue eyes.
Officers say he also has a scar on his forehead and a seven-inch scar on his stomach.
People are asked to report non-immediate sightings to 101, quoting log 1563 of May 30, 2021.