In what environmentalists hailed as a victory for efforts to curb climate change, an appeals panel in Washington on Thursday rebuffed efforts to delay enforcement of President Barack Obama's plan to reduce greenhouse gas emissions until legal challenges are resolved.

The U.S. Court of Appeals for the District of Columbia Circuit issued an order denying requests for a stay that would have barred the Environmental Protection Agency (EPA) from implementing the Clean Power Plan.

The plan has been challenged by more than two dozen mostly Republican-led states and allied business and industry groups tied to fossil fuels. The states deride the carbon-cutting plan as an "unlawful power grab" that will kill coal-mining jobs and drive up electricity costs.

Thursday's order allows federal regulation of carbon emissions pending the court's review of the case, set for June 2.

Obama press secretary Josh Earnest said the White House was pleased with the decision.

"We are confident that the plan will reduce carbon pollution and deliver better air quality, improved public health and jobs across the country," Earnest said. "We look forward to continuing to work with states and other stakeholders taking steps to implement the Clean Power Plan."

West Virginia Attorney General Patrick Morrisey, whose state is heavily reliant on coal mining, said his office would consider urging the U.S. Supreme Court to halt what he termed the "ongoing, irreversible harm" caused by the new federal regulations.

Implementation of the rules is considered essential to the United States meeting emissions-reduction targets in a global climate agreement signed in Paris last month. The Obama administration and environmental groups also say the plan will spur new clean-energy jobs.

The federal plan aims to stave off the worst predicted impacts of climate change by reducing carbon dioxide emissions at existing power plants by about one-third by 2030. The plan also encourages further development of alternative energy sources such as wind and solar by further ratcheting down any emissions allowed from new coal-fired power plants.

Under the Clean Air Act, certain challenges to new EPA rules skip the federal district court and go directly to the appeals court.

"This is a huge win for protecting our health and climate from dangerous carbon pollution," said David Doniger, director of the Climate and Clean Air Program at the advocacy group Natural Resources Defense Council. "The court has brushed aside the polluters' bogus bid to block the Clean Power Plan, and the electricity sector will continue the shift from its high-pollution, dirty-fueled past to a safer, cleaner-powered future."

The Associated Press