The Saskatchewan government says oil from a pipeline has spilled into the North Saskatchewan River.
The province said in an email that a breach was reported on a Husky Energy line upstream of Maidstone on Thursday morning.
It said Husky activated an emergency response team and berms were being used to contain the oil blend near the spill site. Another berm was being set up further downstream near Paynton.
Husky said it shut down the line and was working closely with neighbours and municipalities.
Husky spokesman Mel Duvall said in an email that the amount of oil spilled was still being assessed.
He said the line runs from the company's heavy oil operations to its facilities in Lloydminster and carries oil mixed with a diluent, which is a lighter hydrocarbon that's added to ease the flow.
The province said an environmental protection officer had been dispatched to the site. It also said Husky, with co-operation from the province, was notifying river users downstream of the spill.
In North Battleford, which draws its water supply from the North Saskatchewan River downstream from the spill, city officials said they had been informed and were taking precautions.
Tammy MacCormack, the city's environment manager, said it was unknown how long it would take for the flow to reach North Battleford. But water samples were being done, she said, and supply intakes were to be shut if the oil spill reached the city.
"Our plan is to be shut down when it goes by," MacCormack said. "We will be watching the water."