The White House threatened Tuesday to veto the first bill of the new Republican-controlled Senate -- legislation to approve the Keystone XL oil pipeline -- and in doing so, drew criticism from Senate Majority Leader Mitch McConnell.

"Bipartisan reform can only be achieved if President Obama is interested in it. The president is the only one who can bring his party on board. He's the only one who can sign what Congress passes," McConnell said Wednesday in his first major floor speech as majority leader, reported The Associated Press.

"Threatening to veto a jobs and infrastructure bill within minutes of a new Congress taking the oath of office - a bill with strong bipartisan support - is anything but productive," he added.

On Tuesday, White House press secretary Josh Earnest indicated that Obama would veto two bills currently under review in Congress - one that would approve the Keystone pipeline, and one dealing with Obamacare and the economy, reported Fox News.

The White House then issued formal statements on Wednesday promising to veto the bills should they arrive on Obama's desk.

The Obama administration said it would veto the Keystone legislation because it "seeks to circumvent longstanding and proven processes" and would prevent "the thorough consideration of complex issues that could bear on U.S. national interests (including serious security, safety, environmental, and other ramifications)."

Republicans say that the $8 billion Keystone oil pipeline, which would stretch from Canada's oil sands to the Texas Gulf Coast, would create jobs and reduce U.S. dependency on foreign oil.

As for the threat to veto legislation that would increase Obamacare's definition of a full-time worker from 30 to 40 hours per week, the White House said in a Statement of Administration Policy, "there is no evidence that this has caused a broad shift to part-time work to date," reported The Hill

"By moving the threshold to 40 hours, this legislation could cause the problem it claims to solve by greatly increasing the number of workers for whom employers may have an incentive to reduce hours to avoid the requirement."