Canada's oil industry won't be gushing over a late-night TV appearance by U.S. President Barack Obama, who used an interview with Stephen Colbert to highlight problems with the Keystone XL pipeline project.

"Essentially, there is Canadian oil passing through the United States to be sold on the world market," he said on The Colbert Report Monday night, which was taped live in Washington, D.C. "It's not going to push down gas prices here in the United States. It's good for Canada. It could create a couple thousand jobs in the initial construction of the pipeline, but we've got to measure that against whether or not it is going to contribute to an overall warming of the planet, which could be disastrous."

His comments received boisterous cheers from the George Washington University crowd.

The Canadian government and the oil industry have been waiting six years for U.S. approval of the pipeline, which has repeatedly been held up under Obama's administration.

Polls have shown a majority of Americans support the pipeline project, but it has faced huge opposition from environmental and First Nations groups, and Obama has hinted he would veto the project if it was approved by Congress. When Colbert asked directly if he would sign the bill, Obama didn't respond.