Bison on the loose near Camrose, Alta.

People in the Camrose, Alta., area are being warned to be on the lookout for roaming herds of bison that escaped from a farm Monday night.

RCMP say 30 to 40 head ofbison are loose northeast and northwest of Camrose, southeast of Edmonton.

A number of the animals were also spotted in the city. Police thought they had abouta dozen of the bison corralled onTuesday morning, but they got away.

At6 p.m., about 17 to 20 of the animals were still loose within the city, the CBC's Michael Dick reported.

"Camrose city police have been chasing them around a bit but at this point now we have them all over the city," RCMP Cpl. Jim Link said earlier in the day.

Police said the animals crossed some highways in the area Monday night. They said the bison are travelling in separate herds.

Link says there have been no reports of any collisions with vehicles but there have been complaints about property damage.

Anyone coming across the herds are asked to call RCMP or 911.