BILLINGS, Mont. (AP) — A Canadian company says it has started preliminary work along the proposed Keystone XL pipeline from Canada to the U.S. as opponents wait for a judge to rule on their request to block the project.

TC Energy spokeswoman Sara Rabern said Wednesday the Calgary-based company was moving equipment this week and will begin mowing and felling trees along the pipeline’s 1,200-mile route within the next week or so. The company anticipates starting construction at a northern Montana border crossing next month.

Environmental groups in January asked U.S. District Judge Brian Morris to block all work while a challenge to the project’s permit is pending.