(CNN) Part of the Keystone 1 Pipeline in North Dakota was shut down after a leak of about 9,120 barrels of oil -- 383,040 gallons -- was discovered, TC Energy company said in a statement.

Keystone pipeline leak

The oil leak was discovered just north of Edinburg, in the northeast part of the state, and affected about 2,500 square yards of land, the company said. A drop in pressure was detected on Tuesday, and the pipeline was immediately shut down, the company said.

The company is not sure how the leak started, but says an independent party is examining the pipeline.

"We are establishing air quality, water and wildlife monitoring and will continue monitoring throughout the response. There have been no reported injuries or impacted wildlife," TC Energy said.

"The safety of the public and environment are our top priorities and we will continue to provide updates as they become available."