President Barack Obama has vetoed a bill approving the Keystone XL pipeline, a project that sparked a dispute between environmentalists and oil industry supporters in the United States.
The White House sent notice of the veto to the Senate on Tuesday. It was the third veto of Obama's presidency.
This veto puts a freeze on a top Republican priority, at least temporarily. Earlier this year, the Republican-led Congress approved the bill forcing construction of the pipeline.
Obama, in his notice to the Senate, cited a procedural matter as the reason for his veto.
Shortly before the president issued the veto, White House spokesman Josh Earnest said Congress had passed the bill without waiting for the State Department to conclude a review of the project.
"Through this bill, the United States Congress attempts to circumvent long-standing and proven processes for determining whether or not building and operating a cross-border pipeline serves the national interest," Obama wrote in his veto message.
Earnest indicated there still was a chance the president might approve the project.
"It certainly is possible," he 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.”
Republicans, who support the project because of its job-creation potential, made passing a bill a top priority after gaining control of the U.S. Senate and strengthening their majority in the House of Representatives in November elections.
The House voted 270-152 to pass the bill on February 11 after the Senate approved it January 29.
Neither the House nor the Senate passed the proposal by a wide enough margin to override the expected presidential veto.
Proposed in 2008, the Keystone XL pipeline would move as much as 830,000 barrels of oil a day, largely from Canada, to the Midwestern U.S. state of Nebraska; from there, it would be routed to refineries along the Gulf of Mexico.
Republicans and the oil industry have argued that the $8 billion infrastructure project is about creating jobs and boosting energy security. They say it would import oil from a friendly neighbor and ship it to domestic refineries subject to stringent environmental regulations.
Democrats and their environmental allies have characterized the pipeline plan as a gift to the oil industry that would worsen global warming and subject parts of the U.S. to the risks of an oil spill.
VOA's Luis Ramirez contributed to this report. Some information came from Reuters.