This post has been updated. 

President Obama would veto a bill that would allow for the construction of the Keystone XL pipeline, the White House said Tuesday.

"If this bill passes this Congress, the president wouldn’t sign it," said White House press secretary Josh Earnest.

The White House’s announcement came as the Republican-controlled Congress was being sworn in. GOP leaders have pledged to pass a bill authorizing the pipeline’s construction. Sen. Joe Manchin (D-W.Va.) and John Hoeven (R-N.D.) introduced legislation Tuesday authorizing the pipeline's construction.

“The president is going to see the Keystone XL pipeline on his desk,” Sen. John Barrasso (R-Wyo.) said Sunday on “Meet the Press.”

Senate Democrats narrowly blocked passage of the bill in November. The White House said at the time that the bill was something Obama "doesn't support."

"If this bill passes this Congress, the president wouldn’t sign it either," Earnest said.

Earnest said there is a "well-established process in place" for approving projects such as Keystone. The $7.6 billion project would stretch nearly 1,700 miles and deliver 830,000 barrels of oil a day from western Canada to the United States. Earnest said that because there is a process, Congress should not meddle.

That process is held up by a lawsuit in Nebraska over whether the state legislature could allow the governor to make decisions on the pipeline rather than the state's Public Utilities Commission.

“I think the president has been pretty clear that he does not think that circumventing a well-established process for evaluating these projects is ... the right thing for Congress to do,” Earnest said.

Obama rejected a Canadian firm's application to build the pipeline in 2012.

At a year-end news conference in December, Obama sought to downplay the benefits of the pipeline. He said the benefits for U.S. citizens and workers from the pipeline would be "nominal."

"I think that there’s been this tendency to really hype this thing as some magic formula to what ails the U.S. economy," Obama said.

House Speaker John Boehner said Obama has sided with "fringe extremists" in the Democratic party who do not support Keystone, not Americans who do want the pipeline to be built. Boehner said the veto threat shows that Obama is "hopelessly out of touch" and has "no plans" to listen to his constituents.

"After years of manufacturing every possible excuse, today President Obama was finally straight with the them about where he truly stands.  His answer is no to more American infrastructure, no to more American energy, and no to more American jobs," Boehner said in a statement.

Jack Gerard, chief executive of the American Petroleum Institute, said the group is "very disappointed" by the veto threat.

"And I think it doesn't bode well for relationships between the White House and Capitol Hill" Gerard said. "I'm disappointed the president has made that decision. I'm hopeful he and his advisers will reconsider."

The move angered not just Republicans and oil industry officials but some Democrats such as Manchin.

“It’s the most discouraging thing I’ve ever heard,” Manchin said in a phone interview, minutes after Earnest had made his comments. “For the leader of the country to say basically, ‘Forget it, this is all for naught,’ is not what this country is about, it’s not what we’re all about, and it’s not the process that I’m used to working through.”

Manchin said the move made a mockery of a legislative process under which Democrats as well as Republicans would have a chance to offer amendments to alter the bill. “To say that he won’t give it a chance is absolutely a disservice to our country,” he added.

At the same time that the White House issued its veto threat, Sen. Richard J. Durbin (D-Ill.) objected to the Senate Energy and Natural Resources Committee holding a hearing Wednesday on the Keystone XL bill. Durbin said another Democrat, whom he did not identify, objected to the session.

“While this means we won’t be having a hearing tomorrow, it does not slow down the Keystone XL floor process,” the panel’s spokesman, Robert Dillon, wrote in an e-mail. “Sen. Murkowski was committed to moving legislation through regular committee order and having a robust hearing process. Working with the incoming ranking member, we had lined up witnesses from a labor union and the Center for American Progress (CAP) to testify on the Keystone XL. Democrats will no longer have an opportunity to hear that testimony or make statements. We think that’s unfortunate.”

Environmentalists, meanwhile, lauded the president’s veto threat.

“The new Republican majority in Congress wants to play pipeline politics with our future, and the president is focused on a single question: is the tar sands pipeline in our national interest,” said Bob Deans, a spokesman for the Natural Resources Defense Council. “It’s not.”

Sen. Bernie Sanders (I-Vt.) said he applauds Obama "for standing up to Republicans trying to ram through Congress a bill to let a Canadian oil company ship some of the dirtiest oil on the planet across the United States on its way to overseas markets."

Supporters of Keystone argue that the pipeline will create jobs tied to the pipeline's construction and boost a source of reliable energy, helping the economy. Opponents counter that it will extract oil from dirty tar sands in Canada and do little to help the U.S. economy.

Juliet Eilperin and Lori Montgomery contributed reporting.