BISMARCK, N.D. – The Keystone pipeline has leaked an unknown quantity of oil in northeastern North Dakota.

State Environmental Quality Chief Dave Glatt says regulators were notified late Tuesday night of the leak near Edinburg, in Walsh County.

Glatt says pipeline owner TC Energy shut down the pipeline after the leak was detected. He says the cause and the size of the spill are under investigation.

The Calgary, Alberta-based company says its emergency response team contained the spill to the immediate area of the leak and set up air quality, water, and wildlife monitoring. There have been no reported injuries or impacts to wildlife.

TC Energy says the segment of the pipeline that leaked will be analyzed by the NTSB lab to help determine the cause

The Keystone pipeline is part of a 2,687-mile system that also is to include the proposed Keystone XL pipeline.