President Trump’s pledge that pipeline projects will use “American steel” apparently will not apply to the Keystone XL project, directly contradicting the president’s own words last week.

Politico reported late Thursday night that a White House spokeswoman explained that the project, which has been in the works for a decade, does not count as a “new” or “retrofitted” pipeline and therefore is not subject to Mr. Trump’s made-in-America requirement.

Comments from TransCanada, the company proposing the project, on Friday morning seemed to confirm that it does not plan to use all U.S. steel.

The president in January signed an order calling for all new pipeline projects — or those undergoing significant retrofits or repairs — to “use materials and equipment produced in the United States.”

More broadly, the president has made the use of American steel and other materials in construction projects a centerpiece of his economic pitch.

Last month, in a meeting with leading CEOs at the White House, Mr. Trump explicitly told Mario Longhi, the CEO of U.S. Steel Corp., that Keystone would use American materials.

“And you’re going to be doing pipelines now. You know that, right? We put you heavy into the pipeline business because we approved, as you know, the Keystone Pipeline and Dakota [Access pipeline]. But they have to buy — meaning, steel, so I’ll say U.S. Steel — but steel made in this country and pipelines made in this country,” the president said. “So, the pipe is coming from the U.S.”

Early in his term, Mr. Trump signed an executive order restarting the Keystone XL oil pipeline, which had been shelved under President Obama. When completed, the project will carry 800,000 barrels of oil per day from Alberta, through the U.S. heartland and ultimately to refineries on the Gulf Coast.

After the Obama administration rejected the project, TransCanada filed a $15 billion legal challenge under provisions of the North American Free Trade Agreement. Last week, the company suspended that lawsuit, though it was unclear whether the move was tied to the White House’s decision not to apply the American steel requirement to the Keystone project.

Asked Friday whether the company was committed to using American steel, TransCanada spokesman Terry Cunha reiterated that the company planned to use North American steel for at least 75 percent of the project — with a majority of that coming from the U.S., he said.

He would not say the company planned to use all American materials and would not address specific reports about what the White House had told the company.

“We continue to be encouraged as our presidential permit application makes its way through the approval process,” Mr. Cunha said. “This project will support U.S. energy security, create thousands of well-paying U.S. jobs and provide substantial economic benefits.”

In 2012, the company estimated that about 821,000 tons of steel pipe would be used for the project, including about 660,000 tons for the U.S. portion. Of that, roughly half will be manufactured in Arkansas. Another 24 percent will come from Canada, and about 26 percent of the steel will be made in India and Italy.

But environmentalists, who long have opposed the Keystone pipeline, say the revelations prove that the administration has been outmaneuvered by TransCanada. They also say there is a clear connection between the company dropping its lawsuit and the White House letting it skate on the American steel requirement.

“Donald Trump has sought to portray himself as some sort of master negotiator, but he clearly needs to spend more time in an apprenticeship. Just days ago, Trump pledged before the country and Congress that the Keystone XL pipeline that he was forcing on this country would be made with American steel, but instead, he was outmaneuvered by a foreign company that wants to use imported steel,” Michael Brune, executive director of the Sierra Club, said in a statement.

“The only winner of this ‘deal’ is TransCanada, which is using a $15 billion threat under NAFTA’s deeply flawed corporate tribunal system to outmaneuver Trump and push a dirty and dangerous pipeline across our country,” he said.

Mr. Cunha would not comment on whether there was a connection between the U.S. steel requirement and the NAFTA lawsuit suspension, saying only “the process remains suspended.”