Vancouver police say Lorne Michael Williams, 37, seen in this 2006 photo, is considered a high risk to re-offend. ((Vancouver Police Department))

Vancouver police issued a warning Friday about a man they say is a high-risk sexual offender who poses a risk to young women and may re-offend.

Lorne Michael Williams, 37, now lives in a downtown Vancouver halfway house after recently being released from prison for a string of offences, Const. Tim Fanning said.

Williams had eight convictions, including sexual assault with a weapon, attempted kidnapping, and disguise with intent. He wore ski masks during all the attacks to conceal his identity, Fanning said.

"He is considered a high risk to re-offend," Fanning said.

In 1993, Williams sexually assaulted two women at knifepoint. Eight years later, he attempted twice in a two-week period to abduct two women, who eventually escaped after he tried to force them into a van.

Williams is described as Caucasian, 5-foot-8, about 150 pounds, with brown hair and brown eyes, and a scar on his right hand.

He is not allowed to be with any woman under 19, is barred from any underground parking lot unless accompanied by an adult, and cannot rent or own any vehicles, Fanning said.

Police asked the public to call 911 if they see Williams in violation of any of the conditions for his release.