VANCOUVER -- Police say search crews have run out of places where they can safely look for two men missing since Christmas Day in the back country of Vancouver's North Shore Mountains.

West Vancouver police said Friday that the search for 43-year-old Roy Lee and 64-year-old Chun Lam had been stood down and would not resume unless they received new information.

Officials said a decision had been made between police and North Shore Rescue late Friday to turn the search from a rescue to a recovery operation, meaning the two men are presumed to be dead.

Const. Jeff Palmer said calling off the search isn't something that is taken lightly..

"Unfortunately, there's just no reason to believe that further searching, with all the risks for search and rescue volunteers, will produce a different result," he said.

A missing person's file on the men will remain open, but there is no information to suggest they are anywhere but on the mountain, Palmer said.

Lee and Lum set out from Cypress Mountain Resort in West Vancouver for a day of snowshoeing on Dec. 25. A rescue mission began that night when Lee's car was found empty in the resort's parking lot.

Efforts were hampered by heavy snow, strong winds and the threat of avalanche that forced the temporary suspension of the search on Wednesday.

Conditions improved Friday morning and about 20 highly trained searchers supported by two helicopters returned to comb the Mount Strachan area, hoping to find a trace of the pair.

Air and ground crews were able to extensively search a number of places that weather prevented them from checking in recent days, Palmer said.

There was no sign of the men, he said, and continuing to comb the area would be unsafe for rescuers.

"It is very difficult terrain in there. There's a number of areas that really, simply aren't very safe at any time of the year to search on foot," Palmer said.

North Shore Rescue spokesman Mike Danks said the outcome of the mission is difficult.

"It's really frustrating because so much effort has been put in," he said, noting that the situation could potentially have been avoided if the men had left a trip plan.

"Hopefully, in future, people will see that you absolutely need to be prepared and you have to let someone know where you're going," Danks said.

Palmer acknowledged that the news is extraordinarily difficult for the families involved.

"We really want to be able to bring better news to the families and failing being able to bring them better news, we would hope we could at least bring them closure in a matter like this. And we simply aren't able to do that right now," he said.