Canadian company "TC Energy" announced last Thursday that it temporarily closed the "Keystone" oil pipeline between Canada and the United States after detecting a leak between the states of Kansas and Nebraska.

In a statement, the company clarified that it "mobilized personnel and equipment" following a "confirmed oil leak in a waterway" in Washington County, about 32 kilometers south of the village of Steele City in the state of Nebraska. The pipeline transports crude oil from Canada to refineries in the central western United States and the US Gulf Coast where it is processed to extract gasoline and other petroleum products.

Also, the company statement added: "The affected section was isolated and floating barriers were deployed" to control the leak, and that "the system remains closed as our crews are effectively working to contain and recover the oil," while the emergency response began on Wednesday around 8 PM local time after alerts were issued and a pressure drop was detected in the pipeline system. 

Oil prices initially rose following news of the line closure, but later fell back into the negative territory.