Democratic presidential candidate John Edwards was endorsed Sunday by Friends of the Earth Action, which highlighted his proposal to end global warming and his opposition to new nuclear plants in the United States.

"For these reasons, we trust John Edwards to work for a healthy environment and fight for the rights of regular people in our country and around the world," Brent Blackwelder, the group's president, said in a statement issued by Edwards' campaign.

On the environment, Edwards has proposed capping greenhouse gases beginning in 2010 with a cap-and-trade system. He also has pledged to work for a new climate treaty that includes developing countries, and opposes subsidies for new nuclear power plants in the U.S.

Edwards said he was honored to have the support of the San Francisco-based group, which is the political arm of Friends of the Earth.

"We must work together to halt global warming and protect our natural resources to ensure our children inherit a healthy planet," Edwards said.

On the other side of the political aisle, a Republican environmental group decided to back Sen. John McCain, R-Ariz., for president.

"John McCain is the only Republican candidate in 2008 who understands the deep connection between true conservative values and good environmental stewardship," Martha Marks, president of Republicans for Environmental Protection, said in a statement from McCain's campaign.

"He is the candidate best suited, by knowledge, experience, and conviction, to provide the strong environmental leadership that our country needs," she said.

McCain said he was honored to have the endorsement from the nonprofit organization. Its members, he said, "understand that a healthy environment and a sound economy are essential to our future prosperity."