WASHINGTON — The world's major economic powers are pledging to launch a bold effort to deal with a chronic slowdown in growth and a European debt crisis threatening to push the global economy into another recession. But it was unclear whether their strong words would be backed up by equally strong actions.

The statement by the Group of 20 major economies was issued late Thursday and pledged that the countries, which represent 85 percent of the global economy, would do what was necessary to restore financial stability and clam financial markets which had plunged on Thursday over renewed fears of a global downturn.

The finance officials of traditional economic powers such as the United States, Japan and Germany and major emerging nations such as China, Brazil and India were seeking to demonstrate strong resolve in the hope that it will calm jitters that had sent financial markets down sharply. The United States was represented in the discussions by Treasury Secretary Timothy Geithner and Federal Reserve Chairman Ben Bernanke.

“We are taking strong actions to maintain financial stability, restore confidence and support growth,” the G-20 joint statement said. “We commit to take all actions to preserve the stability of banking systems and financial markets as required.”

The G-20 group had not been scheduled to issue a statement but the market turmoil resulted in a change in plans. The group issued a document that they hoped would demonstrate sufficient resolve.

French Finance Minister Francoise Baroin told reporters the statement represented a “strong global” response to what he called a “very serious situation.”