Hillary Clinton: I oppose Keystone XL pipeline

Monica Alba and Carrie Dann
Hillary Clinton: I oppose Keystone XL
Hillary Clinton outlines drug cost plan
Hillary Clinton: I want to end prescription profiteering

After months of declining to take a position on the Keystone XL pipeline, Democratic presidential candidate Hillary Clinton says she opposes the construction of the project.

"I think it is imperative that we look at the Keystone XL pipeline as what I believe it is: A distraction from the important work we have to do to combat climate change, and, unfortunately from my perspective, one that interferes with our ability to move forward and deal with other issues," she said during a campaign event in Iowa Tuesday.

"Therefore, I oppose it. I oppose it because I don't think it's in the best interest of what we need to do to combat climate change."

File photo: Environmental activists protest against the proposed Keystone XL pipeline in Syracuse, NY in March of 2015
Nicholas Kamm | AFP | Getty Images

Clinton had long cited her former job as secretary of state as a reason to delay weighing in on the deal until the administration formalized its opinion on the project. In July, she said she did not want to "prejudge" President Barack Obama and Secretary of State John Kerry on the result of an administration review of the pipeline's environmental impact.

More from NBC News:
Pope Francis greeted by Obama during first US visit
Trump restarts battle with Fox News
Senate Democrats block 20-week abortion ban bill

But last week, she promised that her decision would be coming "soon" and suggested that she has been growing impatient with the White House for delaying its final verdict on the matter.

"I have been waiting for the administration to make a decision," she said last week in Concord, NH. "I thought I owed them that. I worked in the administration. I started the process that is supposed to lead to a decision. I can't wait too much longer. and I am putting the white house on notice. I'm gunna tell you what I think soon because I can't wait. I thought they would have it decided way, you know, way by now and they haven't."

Clinton has been under fire from fellow Democratic presidential contenders for failing to weigh in on the matter sooner.

"It is hard for me to understand how one can be concerned about climate change but not vigorously oppose the Keystone pipeline," Bernie Sanders, one of Clinton's rivals and a vehement foe of the project, said.

Read MoreThis will be the next spark for a sell-off in oil

Environmental activists vehemently oppose the pipeline, which they say will be vulnerable to leaks, cause harmful effects on the environment and represent a step backward from attempts to address global climate change.

But others, including most Republicans and some pro-business Democrats, say the project would create jobs and carry minimal risk to the environment.