TransCanada Corp is committed to building the $7 billion Keystone XL project despite a 12-to-18-month delay in U.S. approvals, the company's chief executive said on Wednesday.

Even with the delay announced by the U.S. State Department last week, Keystone XL remains the most likely pipeline project to move forward in the mid-term, CEO Russ Girling said. He said the pipeline's importance to the North American economy made its approval essential.

Speaking to a company-sponsored investment conference in Toronto, Girling said he was confident this project will move forward. (Reporting by Scott Haggett; Editing by Frank McGurty)