Updated: 7:10 p.m.

President Barack Obama called the co-chairmen of the super committee today and warned them he would block efforts to partially defuse automatic spending cuts if they fail to cut a deal on deficit reduction.

In separate phone calls to Sen. Patty Murray (D-Wash.) and Rep. Jeb Hensarling (R-Texas), Obama urged them to reach agreement among the 12 members of the Joint Committee on Deficit Reduction.

“The president reminded them that he put forth a very detailed plan for deficit reduction to the committee, and reiterated that any approach must be balanced, and will require tough choices by both sides, including looking at revenues and entitlements,” the White House said in a statement.

“The president also made clear that he will not accept any measure that attempts to turn off part of the sequester,” the statement continued. Some lawmakers, including Sen. John McCain (R-Ariz.), have said they would try to overturn the automatic spending cuts for the Defense Department if the panel fails to reach a deal that shaves at least $1.2 trillion from the deficit.

“Congress must not shirk its responsibilities,” the White House said. “The American people deserve to have their leaders come together and make the tough choices necessary to live within our means, just as American families do every day in these tough economic times.”

In his call with Obama, Hensarling questioned the intent and optics of the president’s threat to veto a package that cuts Medicare and Medicaid but doesn’t raise taxes, according to a readout of the conversation released this evening by the Republican co-chairman’s office.

Hensarling suggested the president clarify why he felt compelled to make such a statement before the panel even had a chance to finish its work.

“Hensarling … discussed his observation that many individuals have interpreted the president’s threatened veto to mean that Democrats could not agree to any health care reforms that would slow the rate of growth for Medicare and Medicaid without also insisting upon a minimum $1 trillion tax increase,” the statement read. “Chairman Hensarling suggested to the president that if this was not his intent, then it would be helpful to the negotiations for that to be clarified.”

The Republican also emphasized that he felt his party had made “a major concession” by including tax code reform in its most recent offer, and called on Democrats to come back with a plan that includes deeper entitlement cuts.

A spokesman for Murray’s office did not immediately respond to comment on whether the Senator would be releasing a statement of her own.

Friday’s two conversations marked a rare moment of engagement from the president, as the White House has largely stayed on the sidelines during the panel’s discussions.

Obama has come under stiff criticism of late from Republicans who believe the administration is banking on failure so it can use the GOP as a foil in next year’s presidential election. The calls were made as Obama jets out of town for most of the next week-and-a-half before the Nov. 23rd deadline for a deal.

The automatic spending cuts triggered by a super committee failure would not begin to take effect until 2013.

McCain said Wednesday he will try to get a consensus within the Senate to overturn the sequester.

“We will work hard to achieve that since all the military leadership, the Secretary of Defense and others have said it would inflict a quickening blow on our national security; we have fairly good ammunition” to win support, McCain said.

Humberto Sanchez contributed to this report.