MIAMI BEACH, Fla. – A bipartisan group of mayors from across the country unanimously backed an ambitious commitment for U.S. cities to run entirely on renewable sources such as wind and solar in two decades.

As the U.S. Conference of Mayors wrapped up in Miami Beach on Monday, leaders from more than 250 cities voted on symbolic resolutions pushing back against President Trump on climate change and immigration.

“Mayors have been involved in the frontline of climate and energy issues for so long, but the president’s actions have really just ignited the excitement of mayors and citizens who want to get to do a whole lot more,” said Steve Benjamin, a Democratic mayor of Columbia, South Carolina, who proposed the resolution with three other mayors.

Most mayors also signed a deal to do their part to uphold the terms of the Paris climate accords, even after the Trump administration pulled out of the agreement. They also strongly rejected plans to increase immigration enforcement and vowed to persuade federal lawmakers to reinstate a popular $3 billion program (Community Development Block Grants) that funds local projects across the country. Trump proposes eliminating the grants.

The clean-energy resolution is one of the many measures that will be sent to Congress and the White House hoping to influence legislation. It was proposed by Democratic mayors in the Republican-dominated states of South Carolina, Texas, Utah and Iowa.

In Washington, Republicans and Democrats remain deeply divided over how to deal with climate change. But cities and states are slowly shaping policies to fight floods and add renewable sources of energy. More than 25 U.S. cities such as San Diego and Salt Lake City have already adopted the clean-energy policy, and six smaller cities including Aspen, Colorado, and Burlington, Vermont, have reached goals of generating 100 percent of the energy through renewable sources.

Traditional energy sources still dominate, with many cities saying they need their states to pass legislation to smooth the transition.

David Sandalow, a former undersecretary of energy in President Barack Obama’s administration who is now at Columbia University’s Center on Global Energy Policy, called it an “ambitious goal.” “(It’s) certainly possible in some cities, much more challenging in others,” he said.

Billionaire and former New York Mayor Michael Bloomberg also addressed the mayors on Monday, announcing a $200 million initiative for cities to take on projects that address issues from climate change to gun violence and immigration.