GLENDIVE, Mont. (AP) — Officials plan to bring in truckloads of drinking water for the 6,000 residents of an eastern Montana city just downstream of an oil spill into the Yellowstone River.

State and federal officials say preliminary tests Monday indicate that at least some oil got into Glendive's public water supply, so they're bringing in outside water as a precaution.

Further tests are planned to determine whether the spill has created any public health threat.

Up to 50,000 gallons of oil spilled in Saturday's pipeline accident. Cleanup crews are being hampered by ice that covers most of the river, making it hard to find the oil.

Wyoming-based Bridger Pipeline Co. accepted responsibility for the spill and has pledged to clean it up.