Jan 5 (Reuters) - The U.S. Department of Transportation's Pipeline and Hazardous Materials Safety Administration (PHMSA) is aware of and monitoring an estimated 60-barrel leak on Colonial Pipeline's Line 3 in Virginia, a source told Reuters on Thursday.

Colonial on Wednesday said it had shut its 885,000 barrels-per-day capacity Line 3 in response to a "product release" at its Witt delivery station near Danville, Virginia, for unscheduled maintenance with an expected restart on Saturday.

The company expects repairs will occur by Friday, the source said, adding that the PHMSA's interstate agent, the VA Corporation Commission, was investigating the leak on the pipeline, which runs from Greensboro, North Carolina, to Colonial's hub in Linden, New Jersey, carrying both gasoline and distillates. (Reporting by Deep Vakil in Bengaluru; Editing by Josie Kao)