Police in Saskatoon are warning owners of diesel trucks about a crime trend that targets them.

In the first half of July, there were 11 reports in the city of diesel particulate filter catalysts being stolen off the bottoms of trucks.

The filters are used to remove soot from the exhaust of a diesel engine, and some cores are made from metal fibres which contain precious metals.

Police spokesperson Kelsie Fraser says the suspects are using some sort of tool to cut and remove the filters.

Fraser says investigators haven't seen the filters pop up online or at scrap metal yards, so they aren't sure what the thieves are doing with them.

She says there are no suspects.