The Obama administration on Tuesday outlined an ambitious plan for slashing U.S. greenhouse-gas pollution over the next decade, calling for accelerating the shift from fossil fuels to clean energy to stave off the worst effects of climate change.

Documents filed with the United Nations formally committed the United States to lowering total U.S. carbon emissions by 26 to 28 percent by 2025, compared with 2005 levels. White House officials called the plan “ambitious and achievable,” and said the pollution cuts could be made without hampering economic growth.

Congressional Republicans immediately attacked the proposal. Senate Majority Leader Mitch McConnell  (R-Ky.) issued a statement cautioning other countries against entering an “unattainable”  climate deal with the United States, given Congress’s intention to block the White House’s pollution-cutting initiatives.

Administration officials said most of the reductions would come from regulations already approved or proposed, including tougher fuel-economy standards for vehicles and a proposed curb on carbon emissions from coal-fired power plants.

“We have the tools we need to meet this goal and to take action on climate pollution,” Brian Deese, a senior adviser to President Obama on climate change, told reporters. “And we know that this is good for our economy, good for our health, and good for our future.”

The documents filled in the details of a pledge made in November, when the United States and China jointly announced commitments to dramatically reduce carbon pollution. Altogether, 30 countries, representing nearly 60 percent of the world’s greenhouse gas emissions, have submitted pledges to the United Nations Framework Convention on Climate Change, and scores of others are expected to do so over the next seven months in preparation for international talks in Paris late this year on a proposed climate treaty.

The details of the U.S. commitments come less than a week after Mexico vowed to cut its greenhouse gases by 22 percent, becoming the first emerging-market country to announce a commitment leading up to the Paris talks. Mexico also said it would make 2026 its peak year for emissions, promising that pollution levels would decline after that.

Negotiators are hoping to use the individual pledges as a basis for a historic pact intended to gradually halt the growth of heat-trapping carbon in the Earth atmosphere. Scientists warn that some effects of global warming — such as melting ice sheets and rising sea levels — are now unstoppable, but an ambitious global pact could still prevent the worst impacts.

White House officials said the pollution cuts would reduce the threat of climate-related disruptions while also delivering tangible improvements in air quality and energy efficiency. Improved fuel-economy standards will allow Americans to spend less money at the gasoline pump, and reductions in smog and soot from coal-fired power plants will improve air quality and prevent thousands of premature deaths each year from respiratory diseases, Deese said.

“Carbon will cost far more in the long run,” Deese said. ” So we think this is an economically sound, ambitious, but achievable goal.  And our hope is that by submitting our [plan] we can continue to encourage countries to follow the lead of countries like China and Mexico and the European Union to make commitments in advance of Paris. ”

Republican Congressional leaders have already vowed to block the administration’s pollution measures, and several key Republicans repeated the threat on Tuesday. McConnell, in his statement, said other countries shouldn’t count on the United States meeting the White House’s targets.

“Considering that two-thirds of the U.S. federal government hasn’t even signed off on the clean-power plan and 13 states have already pledged to fight it, our international partners should proceed with caution before entering into a binding, unattainable deal,” McConnell said.

Environmental groups applauded the president’s pollution-cutting-plan. Jennifer Morgan, director of the climate-change program at the World Resources Institute, said the U.S. pledges showed that the administration was prepared to “lead by example on the climate crisis.”

“This is a serious and achievable commitment,” Morgan said.

But other activists said the United States should be doing much more. Lou Leonard, vice president for climate change at the World Wildlife Fund, said the 28-percent goal “must be a floor, not a ceiling.”

“As the largest contributor to climate impacts already here today, the United States has a responsibility to lead and do its fair share,” Leonard said. “When compared to what scientists warn us is needed to avoid the worst impacts to our cities, our food systems and water supplies, the U.S. pledge falls short.”