President Barack Obama has rejected the Keystone XL oil pipeline project.
The project involved building a 1,900-kilometer oil pipeline to transport Canadian crude oil to southeastern U.S. states.
Obama made his decision after the U.S. State Department reviewed the proposed project. The review said the project "would not serve the national interest of the United States.
The decision is considered a victory for environmentalists.
The announcement comes ahead of a United Nations conference on climate change in Paris. The conference begins on Nov. 30. There, Obama is expected to urge nations to adopt stronger measures to help reduce global warming.
Obama said building the Keystone XL pipeline would not make a "meaningful, long-term contribution" to America's economy. He also said it would not lower gas prices for consumers and would not increase U.S. energy security.
The pipeline would have transported more than 800,000 barrels per day from the oil sands of Alberta, Canada. TransCanada was the company behind the plan.
Many Republican lawmakers supported the construction of the pipeline. They argued it would create jobs, reduce oil prices, and reduce America's dependency on foreign oil.
Leaders of the Republican-controlled Congress reacted strongly to the announcement. House Speaker Paul Ryan called the move "sickening" and "just wrong."
Many Democrats, including presidential candidate Bernie Sanders, applauded the decision.
The president said his administration has aimed to reduce America's dependence on foreign oil and increase its use of clean energy. He said those efforts show the world that the U.S. is a global leader on the environment.
America is "leading by example," he said, and approving the Keystone XL pipeline "would have undercut this global leadership."
Newly elected Canadian Prime Minister Justin Trudeau supported the pipeline project. He voiced his disappointment in Obama's decision, but said the Canada-U.S. relationship is "much bigger than any one project."
I'm Jonathan Evans.
Mary Alice Salinas wrote this report for VOANews.com Ashley Thompson adapted the story with additional reporting from Reuters. Hai Do was the editor.