"I would absolutely approve it, 100 percent, but I would want a better deal," Trump told reporters at a press conference in Bismarck, North Dakota, where he was scheduled to give a speech to an oil conference on the energy policies he would pursue if elected to the White House.

"I want it built, but I want a piece of the profits," Trump said. "That's how we're going to make our country rich again."

The Obama administration's decision to reject the Keystone XL pipeline last year was a huge symbolic victory for America's environmental movement, which had campaigned for years against the project on the grounds that it would accelerate global warming.