President Barack Obama is preparing to announce steps to address climate change, including regulating carbon emissions from existing power plants in the U.S., as early as next week, media reports said on Wednesday, quoting senior administration officials.

Obama’s plans for tackling the climate change issue will be a "second-term priority," Heather Zichal, deputy assistant to the president for energy and climate change, said at a forum organized by the New Republic magazine, Reuters reported. Zichal added that Obama’s measures will not require new funding or legislation by Congress.

The Obama administration plans to enhance standards for energy efficiency in appliances; expedite the development of clean energy on public lands; and, use the Clean Air Act to reduce emissions in the power and energy sectors, Reuters reported Zichal as saying.

Zichal, the Reuters report said, ruled out a tax on carbon emissions -- a move opposed by Republicans -- but called on Washington lawmakers to reach a consensus on the issue.

"It's time to turn this issue from a red state-blue state issue into an American issue.”

A New York Times report, quoting an administration official, said Obama's new policy, which could be released as early as next week, could include new initiatives on renewable power and energy efficiency. Electric power plants are the largest source of pollution, causing global warming in the country and are responsible for nearly 40 percent of greenhouse gas emissions, the report noted.

Obama’s announcement will follow withering criticism, which has picked up in recent weeks, from various quarters for not delivering on campaign promises.

"I really can't understand why they haven't moved forward on this more quickly, and we hope that turns around," Nathan Wilcox of Environment America told CBS News.

Last week, former Vice President Al Gore urged Obama to move beyond "great words" to "great actions," while many environmental groups and states have threatened to sue the Obama administration to force cuts to power-plant emissions, according to CBS News.

At the same time, however, Obama’s climate change strategy could provoke legal action from Republicans and certain industries, the Times report said, noting that reforms on power-plant emissions have been one of the most closely-followed within the larger climate change legislation.

"Our dangerous carbon emissions have come down, but we know we have to do more. And we will do more," Obama said on Wednesday in a speech in Berlin, where he is currently in talks with Chancellor Angela Merkel, after the G-8 summit in northern Ireland, which concluded Tuesday.