Two roughnecks work a drilling rig north of Port Arthur, Tex., on Sept. 12, 2012. (Michael S. Williamson/The Washington Post)

This post has been updated. 

President Obama vetoed a bill authorizing the controversial Keystone XL pipeline Tuesday, carrying out a threat to reject one of the first measures the Republican-led Congress sent to the president's desk.

"Because this act of Congress conflicts with established executive branch procedures and cuts short thorough consideration of issues that could bear on our national interest -- including our security, safety, and environment -- it has earned my veto," Obama wrote in a message to the Senate.

White House Press Secretary Josh Earnest said earlier Tuesday that Obama planned to veto the bill because the State Department is still conducting a review of whether the massive pipeline — which would transport roughly 800,000 barrels of heavy crude from Hardisty, Alberta, to refineries in Port Arthur, Tex. — would serve the national interest.

President Obama vetoed a bill authorizing the controversial Keystone XL pipeline, carrying out a threat to reject one of the first measures the Republican-led Congress sent to the president's desk. (Reuters)

"Through this bill, the United States Congress attempts to circumvent longstanding and proven processes for determining whether or not building and operating a cross-border pipeline serves the national interest," Obama wrote.

Congressional Republicans sent a bill authorizing the pipeline to the president's desk Tuesday. It is the third veto Obama has issued, and Earnest said earlier Tuesday it would be done "without any fanfare or delay."

He did not rule out Obama eventually approving the pipeline.

"It certainly is possible," Earnest said. "The president will keep an open mind as the State Department considers the wide range of impacts that this pipeline could have on the country, both positive and negative."

Two-thirds of each chamber would need to vote to override Obama's veto — something that seems unlikely, given the votes that passed the bill.

Reaction from both supporters and detractors was swift. Supporters of the pipeline argue that it would create construction jobs and increase the a supply of reliable energy, lowering oil prices and bolstering the economy. Those opposed to the project say that it would accelerate climate change by speeding the energy-intense extraction of bitumen in Alberta, could pollute waterways along the project's route and would do little to help the U.S. economy. Environmentalists have said approving or rejecting the pipeline is akin to a vote on climate change.

[Will Keystone XL pipeline create 42,000 ‘new’ jobs?]

“The president’s veto of the Keystone jobs bill is a national embarrassment," House Speaker John Boehner (R-Ohio) said in a statement. "It’s embarrassing when Russia and China are plowing ahead on two massive pipelines and we can’t get this one no-brainer of a project off the ground.  The president is just too close to environmental extremists to stand up for America’s workers."

Republican National Committee Chairman Reince Priebus said the veto shows that Obama is "out of step" with Americans who support the project.

“The least President Obama can do is look the American people in the eye when he is so blatantly defying them," he said in a statement.

Sierra Club Executive Director Michael Brune said that Obama "kept his word" and rejected the bill.

"That’s what he said he’d do from the start, but Republicans in Congress continued to waste everyone’s time with a bill destined to go nowhere, just to satisfy the agenda of their big oil allies," Brune said in a statement. “President Obama has also made it clear he will reject the tar sands pipeline if it contributes significantly to the climate crisis. The president has all the evidence he needs to reject Keystone XL now, and we are confident that he will."

Sen. Bernie Sanders (I-Vt.) also praised Obama for vetoing the measure.

"This veto tells the world that our nation takes seriously the planetary crisis of global warming and that we will not support legislation that would let a Canadian oil company ship some of the dirtiest oil on the planet across the United States," Sanders said in a statement.

But not all Democrats agreed. Sen. Heidi Heitkamp (N.D.), a longtime supporter of the pipeline, said in a statement that "watching a bill that inched toward this consensus over six years to bring our country closer to an energy independent future is downright disappointing."

TransCanada, the project's sponsor, said in a statement the company "remains fully committed to Keystone XL despite today’s veto of bipartisan legislation in support of the project.... Without Keystone XL, U.S. refineries are forced to use other methods of transportation to get the oil they need for creating products we all rely on every day."

Regardless of the project's fate, the veto highlighted the ongoing tensions between the White House and congressional Republicans.

“There are areas where we will disagree with what Congress is doing, but we don’t think that should preclude us from working on areas where there is common ground,” Schultz said in a phone interview, adding Republicans have the option of picking fights or working together. “It can largely be up to Congress for what they choose to be doing.”

Boehner spokesman Cory Fritz said in an e-mail that Obama bore the blame for Washington's inaction.

“If the president’s going to veto popular jobs bills, like Keystone XL, and refuse to lend a hand to stop his party’s filibusters in the Senate, it will be tougher to forge agreements on any number of issues, including our shared priorities," Fritz wrote. "There’s no doubt about it.”

The House passed a bill authorizing construction of the pipeline earlier this month by a vote of 270-152, mostly along party lines. The Senate passed the measure 62 to 36 in January. The bill was one of the first introduced as the Republican-controlled Congress was being sworn in last month. In November, Senate Democrats narrowly blocked passage of a bill authorizing construction of the pipeline.

Last month, the Nebraska Supreme Court ruled that construction of the pipeline could go forward after a group of landowners opposed to the project sued to block it from being built. Obama had cited the court case as a reason to delay a final decision on the project. The company looking to construct the pipeline, TransCanada, soon after filed paperwork to use eminent domain to acquire land for the project; a Nebraska court issued a temporary injunction earlier this month barring the company from using eminent domain.

At a news conference in December, Obama downplayed the potential benefits of the pipeline.

"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.

Obama rejected an application from TransCanada to build the pipeline in 2012 and The Post reported in November that Obama will likely deny the company's final permit for the project.

The $7.6 billion project would stretch nearly 1,700 miles.