TransCanada is building a 485-mile pipeline from the Cushing, Okla., oil storage hub to refineries along the southern U.S. coast. Construction crews have been met by activists from pipeline opposition group Great Plaints Tar Sands Resistance.
TransCanada filed a lawsuit seeking a restraining order against the group and about two dozen people involved in protests.
"The temporary restraining order we are seeking would protect our ability to construct the pipeline under the law," TransCanada spokesman Jim Prescott was quoted by The Oklahoman as saying. "It also is an effort to respect landowners' rights and the safety of the men and woman who are building the safest pipeline system in America."
Three protesters were barred by an Oklahoma county judge from trying to interfere with pipeline construction, which should be completed by summer. Great Plaints Tar Sands Resistance said the restraining order is tantamount to an assault on free speech.
The pipeline would carry oil sands, a controversial type of crude oil viewed as more harmful to the environment than conventional crude oil.