By Jeff Mason and Richard Cowan
WASHINGTON, Feb 24 (Reuters) - President Barack Obama on Tuesday swiftly delivered on his vow to veto a Republican bill approving the Keystone XL oil pipeline from Canada, leaving the long-debated project in limbo for another indefinite period.
The Senate received Obama's veto message and Senate Majority Leader Mitch McConnell immediately countered by announcing the Republican-led chamber would attempt to overturn the veto by March 3.
Obama rejected the bill hours after it was sent to the White House. Republicans passed the bill to increase pressure on Obama to approve the pipeline, a move the president said would bypass a State Department process that will determine whether the project is in the U.S. national interest.
"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 in his veto message.
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 bill passed by 270-152 in the House earlier this month and cleared the Senate in January. Despite their majority in the Senate, Republicans are four votes short of being able to override Obama's veto.
They have vowed to attach language approving the pipeline in a spending bill or other legislation later in the year that the president would find difficult to reject.
Obama has played down Keystone XL's ability to create jobs and raised questions about its effects on climate change. Environmentalists, who made up part of the coalition that elected the president in 2008 and 2012, oppose the project because of the carbon emissions involved in getting the oil it would carry out of Canadian tar sands.
TransCanada Corp's pipeline would carry 830,000 barrels a day of mostly Canadian oil sands petroleum to Nebraska en route to refineries and ports along the U.S. Gulf. It has been pending for more than six years. (Additional reporting by Timothy Gardner and Susan Cornwell; Editing by Peter Cooney)