Republicans controlling the House announced plans Wednesday to cut $30 billion from the day-to-day budgets of Cabinet agencies, doubling down on cuts to domestic programs just weeks after a split-the-differences bargain with President Barack Obama.

The moves by the powerful lawmakers atop the House Appropriations Committee are the first concrete steps to try to implement a tight-fisted 2012 budget plan approved by Republicans’ last month. It would build on $38 billion in savings enacted in a hard-fought agreement with Obama over the current year’s budget.

The $30 billion in savings from agency operating budgets that have to be annually approved by Congress seems small compared to deficits that could top $1.6 trillion this year. But they’re actually a key building block in eventually wrestling the deficit under control, assuming Congress can make the cuts now and stick with them year after year in the face of inflation.

That’s a big “if.”

Obama and his Democratic allies controlling the Senate are sure to battle hard against cuts of this size, even though Obama told Senate Democrats Wednesday not to adopt unyielding positions in their budget talks with Republicans. Obama, meeting with senators at the White House, even cautioned that painful cuts are in store to achieve a bipartisan agreement on deficit reduction, according to Senate Democratic leader Harry Reid of Nevada.

Reid said Obama told them not to do what he contended Republicans have done: “Drawing these lines in the sand. We can’t do that.”

Obama on Wednesday also said lawmakers may have to rely on automatic spending cuts and tax increases to reach a deal on deficit reduction.

“I think what we’re going to end up having to do probably is to set some targets and say, you know, those targets have to be hit if not automatically, some cuts and tax increases start taking place,” Obama told CBS News. “And that will give incentive for us to negotiate and figure something out.”

Republicans have strongly opposed any mechanism that would trigger a tax increase to close the deficit.

Under the House Appropriations Committee plan, the cuts to domestic programs like education, housing subsidies and infrastructure projects will feel much more severe because the Pentagon — which accounts for more than half of the budget that passes through the Appropriations panel each year — would actually receive a $17 billion, 3 percent boost. Domestic agencies and foreign aid accounts would have to absorb $47 billion in cuts, averaging about 9 percent.

“Brutal … brutal,” said Rep. Norm Dicks of Washington, the top Democrat on the Appropriations panel, who warned of cuts to food inspection, Pell Grants that provide college aid for low-income students, community development grants, food aid to low-income pregnant women and their children, and grants to community action agencies that serve the poor. “Those are all things that are going to hurt the lowest-income people in this country.”

A third of the entire budget passes through the Appropriations panel, once reviled in some GOP circles for its free-spending ways and addiction to home-state projects known as earmarks. The spending bills are likely to produce a long, angry summer of House floor fights, but the ultimate fate of the spending bill probably lie in broader budget talks with the White House involving must-do legislation to allow the government to continue to borrow to meet its obligations. The Senate has yet to pass a budget blueprint that’s a precursor to action on spending bills.

Appropriations Committee Chairman Harold Rogers, R-Ky., released a broad outline of the panel’s plan to cut $30 billion from appropriated accounts. That’s on top of $38 billion carved from agency budgets in last month’s spending showdown legislation and it keeps a campaign promise to bring domestic agency budgets, on average, to levels in place before Obama took office. The slow, steady advance of the actual legislation begins in two Appropriations subpanels on Friday.