Husky Energy said it reported anomalies on a pipeline system the night before it ruptured and released oil into the North Saskatchewan River.

Responders working with the Canadian company are cleaning up after about 1,550 barrels of oil was released about a quarter mile from the banks of the North Saskatchewan River. The company said it recorded pressure anomalies one week ago on several segments of the pipeline system the night before the spill.

"As per our normal procedures when we note such anomalies, we immediately began reviewing data and operating characteristics," the company said in a statement. "As a precaution, crews were dispatched along the gathering system and did not identify a leak."

Sheen was reported on the North Saskatchewan River on the morning of July 21.

The heavier type of oil found in Canada has the potential to sink in water and mix in with river sediment, making cleanup operations complex.

Provincial leaders have erected river barriers and other containment features to control the spill, though residents were advised to conserve water during the response effort. Earlier this week, the city government in Prince Albert declared an emergency and shut down the local intakes for a water treatment plant along the river because sheen had migrated toward its systems.

"Husky is committed to completing a full and thorough investigation, in active cooperation with the relevant authorities," the company said.

The company said water monitoring and environmental sampling is ongoing.

A pipeline is under construction to bring water from the South Saskatchewan River. No timeline for completion was listed.