Alberta's Energy Regulator says a pipeline has leaked crude oil in southwestern Alberta.

AER spokeswoman Monica Hermary says Husky Energy of Calgary reported the spill at Cox Hill Creek on Thursday around 3 p.m.

Cox Hill Creek is about 22 kilometres west of Bragg Creek, an area popular for hiking, camping and other outdoor recreation.

Hermary says it's not known how much crude has leaked, but adds the oil has affected the creek.

She says the pipeline was shut and depressurized on Thursday and no more oil is flowing through that section of the pipeline.

Husky said it has a response team at the site and cleanup efforts are underway, but the company did not say how much oil was spilled.