White House press secretary Jay Carney blasted Rep. Greg Walden (R-Ore.) on Thursday after the National Republican Congressional Committee chairman accused the president of a "shocking attack on seniors" with the inclusion of chained CPI in his budget proposal.

Chained CPI — a way of calculating benefits that would ultimately shrink Social Security checks — has been long championed by House Republicans, and was included by President Obama in his plan to signal a willingness to compromise on entitlement reform.

"This is a Republican proposal," Carney said Thursday. "And cynical attempts to make it otherwise by some represent, I think, dissonance within the Republican Party, and we've seen plenty of condemnation from conservatives and Republicans of that sort of flagrantly ridiculous and cynical attempt to disown a proposal that emanated from Republican leaders."

Walden made the comment Wednesday during an interview with CNN.

"I thought it very intriguing in that the budget really lays out kind of a shocking attack on seniors, if you will," the Oregon lawmaker said. "And we haven't seen all the detail yet, and we'll look at it, but I'll tell you, when you're going after seniors the way he's already done on ObamaCare, taking $700 billion out of Medicare to put into ObamaCare, and now coming back at seniors again, I think you're crossing that line very quickly here in terms of denying access to seniors for health care in districts like mine, certainly, and around the country. I think he's going to have a lot of pushback from some of the major senior organizations on this and Republicans, as well."

The remark earned immediate criticism from conservative groups, including the Club for Growth.

"Greg Walden doesn't seriously oppose even the most modest of reforms to Social Security, right?" Club for Growth President Chris Chocola said. "With nearly $100 trillion in unfunded liabilities, the last thing Republicans should attack the Democrats for is for making the most minor reforms to our entitlement programs."

At the White House, Carney cited media reports in which aides for Senate Minority Leader Mitch McConnellAddison (Mitch) Mitchell McConnellSessions: 'We should be like Canada' in how we take in immigrants NSA spying program overcomes key Senate hurdle Overnight Finance: Lawmakers see shutdown odds rising | Trump calls for looser rules for bank loans | Consumer bureau moves to revise payday lending rule | Trump warns China on trade deficit MORE (R-Ky.) and Speaker John BoehnerJohn Andrew BoehnerDems face hard choice for State of the Union response Even some conservatives seem open to return to earmarks Overnight Finance: Trump, lawmakers take key step to immigration deal | Trump urges Congress to bring back earmarks | Tax law poised to create windfall for states | Trump to attend Davos | Dimon walks back bitcoin criticism MORE (R-Ohio) advocated for the cuts.

"The inclusion of entitlement reform, specifically chained CPI and means testing of Medicare, comes at the specific behest and request of Republican leaders, as you know," Carney said.