President Obama pledged Wednesday to halt tax cuts for American households making more than $250,000, saying in his first press conference since re-election that voters had embraced his plan for avoiding the so-called fiscal cliff looming at the end of the year.

"What I'm not going to do is to extend Bush tax cuts for the wealthiest 2 percent that we can't afford and according to economists will have the least positive impact on the economy," the president said from the East Room of the White House, highlighting income tax breaks for people making more than $200,000 and households making more than $250,000 annually. "More voters agreed with me on this issue than voted for me."

The president said he was willing to compromise on other ways to raise revenue -- leaving open the possibility for tax reforms that Republicans are more likely to embrace -- but stood firm on one of the central tenants of his re-election campaign: that the wealthy must contribute more in taxes to plug a soaring national deficit.

When reminded that he had caved before on raising such tax rates, Obama replied, "What I said at the time was what I meant, which is that this was a one-time proposition."

Wednesday marked Obama's first extensive question-and-answer session with the White House press corps since March. The usually quiet lame-duck session has become a crucial test for the president, who must navigate the fiscal cliff negotiations in addition to the recent resignation of CIA Director David Petraeus and persisting questions about the Sept. 11 attacks in Benghazi, Libya, that killed four Americans.

But the ongoing struggle with congressional Republicans over cutting the budget and raising revenues remained the top priority. Obama said Congress should go ahead and push though tax breaks for middle-class families that are set to expire on Jan. 1, while debating how to handle tax rates for the wealthiest Americans.

And the president conceded Wednesday that climate change legislation, which some liberals have pushed for in the wake of last week's election, was not high on his priority list.

"Look, we're still trying to debate whether we can just make sure that middle-class families don't get a tax hike," he said. "Let's see if we can resolve that. That one's easy,"

Administration officials will meet with congressional leaders Friday at the White House, where Obama will push for $1.6 trillion worth of added taxes on the wealthy and corporations over the next decade. Republicans have balked at that figure because that's twice the amount of taxes that House Speaker John Boehner, R-Ohio, had agreed to during negotiations to raise the debt ceiling last year.

The GOP is calling for closing special-interest loopholes in the tax code, paired with overall tax and entitlement reform.

Senate Minority Leader Mitch McConnell, R-Ky., reacted to Obama's press conference by calling for the administration to propose a plan that can garner Republican support and "that has a realistic chance of becoming law."

And some analysts questioned Obama's firm stance ahead of those negotiations.

"The president is still dealing with a 51-49 country, and I don't think too many people would say he has a mandate," said Patrick Griffin, a GOP strategist. "Clearly, he's not starting in the middle with these negotiations. There's no incentive for Republicans to go that far in raising taxes."

However, Dean Baker, co-director of the Center for Economic and Policy Research, countered, "The president is in a very good position with Republicans. Do you want to give a tax break to 98 percent of people or not?"