An ExxonMobil pipeline running under the Yellowstone River burst Friday night, spilling black crude oil rushing into the river and forcing residents downstream to evacuate, authorities said.

The bridge across the Yellowstone River at Laurel Montana. [Environment News Service]

The spill that was detected early Saturday came from a crude oil pipeline that runs from Silver Tip to Billings, Montana, the ExxonMobil Pipeline Company said in a statement.

The oil spill comes after the swollen Yellowstone River overtopped its banks, flooding Riverside Park and closing a county road south of the Laurel.

Exxon said that pipeline pumps were shut down within seven minutes of pressure loss. It estimates that the equivalent of 750 to 1,000 barrels of crude oil leaked into the river.

Nearby residents in Laurel, Montana, were evacuated in the wee hours of the morning but were able to return to their homes by 6 a.m., said a spokesman for Laurel City Fire and Ambulance.

An ExxonMobil official said the damaged pipe is buried six feet below the riverbed. The park has been closed for since late May because of high water and flooding.

"At this early stage, we have no information on the cause of the incident, and we are working to determine the amount of oil released." ExxonMobil said.

The company also said that crews from its nearby Billings, Mont., refinery responded to the leak on Saturday, using boom and absorbent pads to pick up oil. Fifty more oil spill response specialists were expected to join the clean-up effort Sunday.