UPDATE April 8, 6:26 p.m.: TransCanada announced Friday afternoon the Keystone pipeline will re-start after the leak has been repaired, but the company said in a later news release that initial plans to restart the pipeline on Saturday may be delayed.

"Working with PHMSA, TransCanada engineers and pipeline integrity specialists have worked to take the necessary actions that will ensure safe and reliable delivery of crude oil," the company said in a news release. "As part of the conditional re-start, TransCanada will operate the pipeline at a reduced pressure to ensure it is functioning appropriately and meeting the conditions set out by PHMSA. "

CALGARY — TransCanada engineers and the U.S. pipeline regulator are working out the best way to fix a segment of the Keystone system that spilled oil in South Dakota.

The Calgary-based company says crews safely dug up about 84 metres of pipe to find the leak.

Once repairs are complete, TransCanada and the Pipeline and Hazardous Materials Safety Administration will work on returning the 590,000-barrel-a-day line to service.

The company estimates about 63,600 litres — or 400 barrels — of crude leaked about 60 kilometres southwest of Sioux Falls, S.D. The spill was discovered by a passerby, and didn't get flagged by TransCanada's automatic pipeline leak detection systems.

TransCanada says there's been no threat to public safety or apparent significant environmental impact.

The cross-border system, which has been in operation since 2010, is not expected to reopen until at least early next week.

The proposed Keystone XL pipeline, which was rejected by U.S. President Barack Obama in November, would have been an expansion to the existing system, providing a more direct route for oilsands crude to reach Gulf Coast refineries.