Back when Barack Obama was still an Illinois state senator, he was known among fellow lawmakers as a formidable poker player.

On Tuesday, the US president called Republicans' bluff on the Keystone XL pipeline.

Heading into a legislative showdown with the GOPcontrolled House of Representatives, the White House formally stated Obama's intention to veto legislation that would force his administration to speed up a decision on the controversial oilsands pipeline.

In a policy statement, the White House denounced a Republican bill that links a politically popular payroll tax-cut extension to the permitting of Keystone XL.

"With only days left before taxes go up for 160 million hardworking Americans, (the Republican legislation) plays politics at the expense of middle-class families," the statement said. "This debate should not be about scoring political points."

The White House veto pledge came hours before the House of Representatives, in a vote Tuesday evening, passed legislation that would maintain a $1,000-a-year reduction in payroll taxes and provide continued aid for unemployed U.S. workers.

Against Obama's wishes, Republicans attached an unrelated legislative "rider" that would force the State Department to make a decision on Keystone XL within 60 days of receiving an application from Calgary-based TransCanada Corp.