President Obama on Wednesday defended the administration's review of the Keystone XL pipeline, while allowing that the process might seem “laborious” to Canada, which has urged the U.S. to quickly approve the project.

“There is a process that has been gone through. And I know it's been extensive and at times, I'm sure, [Canadian Prime Minister] Stephen [Harper] feels, a little too laborious,” said Obama, flanked by Harper and Mexican President Enrique Pena Nieto, during a joint press conference at the North American Leaders Summit in Toluca, Mexico.

But Obama added that the lengthy study of the pipeline’s effects was how the U.S. made “decisions about something that could potentially have [a] significant impact on America's national economy and our national interests.”

“The State Department has gone through its review. There's now a comment period in which other agencies weigh in,” Obama continued. “That will be evaluated by Secretary of State [John] Kerry, and we'll make a decision at that point.”

Canada has urged the U.S. to approve the project which would carry oil to the gulf coast, but environmental groups — which strongly backed Obama’s re-election bid — oppose the pipeline.

The State Department last month unveiled their report on the environmental effects of the pipeline, finding that it would not have a significant effect on greenhouse gases. The department must still make a decision, 90 days after that report, on whether the pipeline is in the nation’s interest — a finding which will be followed by a final decision from the White House.

Supporters of the project hailed the report, and Harper said that he would raise the issue with Obama at the Mexico summit. Congressional Republicans seized on the State report, saying that the president should quickly approve the project, but the White House has said they will allow the process to carry on unimpeded.

Obama said that he had discussed the issue with Harper and said their two nations had a “shared interest in working together around dealing with greenhouse gas emissions.”

“I said previously that how Keystone impacted greenhouse gas emissions would affect our decision,” he added. “But frankly, it has to affect all of our decisions at this stage because the science is irrefutable. We're already seeing severe weather patterns increase. That has consequences for our businesses, for our jobs, for our families, for safety and security.”

Obama said climate issues must be addressed by the international community, but that the U.S. and Canada must take the lead.

“This will be a joint effort,” said Obama. “I'm very eager to consult with Stephen around those issues. And Keystone will proceed along the path that's already been set forth.”

Harper at the press conference said he had “an exchange” with Obama about the pipeline, noting that his views “in favor of the project are very well known.”

The Canadian leader said that climate change was a “shared concern” and that Ottawa and Washington cooperated closely on the issue.