A US judge on Monday rejected a motion by fugitive filmmaker Roman Polanski seeking assurances that he can return to the United States without fear of being jailed for having sex with a minor four decades ago.

The Oscar-winning director of "The Pianist" and "Chinatown" went on the run after spending 42 days in prison for the statutory rape of a 13-year-old at film star Jack Nicholson's house in Los Angeles in 1977.

"Judge (Scott) Gordon has ruled that (the) defendant's motions and corresponding requests are denied," a document from Los Angeles Superior Court said.