PITTSBURGH - The Group of 20 rich and developing nations declared their crisis-fighting efforts a success on Friday and promised to give rising powers such as China more say in rebuilding and guiding the global economy.

In a final statement released at the conclusion of the two-day meeting, the G20 pledged to keep emergency economic supports in place until sustainable recovery is assured, launch a framework for acting together to rebalance economic growth, and implement tougher rules governing banks by 2012.

Here in Pittsburgh, leaders representing two thirds of the planet's population have agreed to a global plan for jobs, growth and a sustained economic recovery, Prime Minister Gordon Brown said.

U.S. President Barack Obama's first turn hosting a major summit ended on an upbeat note, with leaders claiming victory in stopping the recession from turning into a depression.

It worked, they said in the final communique. Our forceful response helped stop the dangerous, sharp decline in global activity and stabilise financial markets.

The Pittsburgh gathering was the third summit in a year for the G20, which said it would now be the premier forum for economic cooperation, supplanting the Western-dominated G7 and G8, which were the primary international forums for decades.

The move was a clear acknowledgment that fast-growing countries such as China and India now play a much more important part in world growth.

This movement to the G20 and away from the G7 is recognizing economic realities. You can't talk about the global economy without having the major dynamic emerging economies at the table, John Lipsky, the deputy managing director of the International Monetary Fund, told Reuters Television.

Disclosure of a second Iranian uranium enrichment plant gave Obama, with the leaders of Britain and France at his side, an opportunity to press for united action against Tehran over its disputed nuclear program.

JOB NOT DONE

Tough economic tasks remained.

The G20 vowed not to return to the reckless behaviour blamed for triggering the financial crisis, which exploded two years ago when failing U.S. mortgage loans caused catastrophic losses at financial firms around the world.

A sense of normalcy should not lead to complacency, the G20 leaders said in the communique.

We want growth without cycles of boom and bust and markets that foster responsibility not recklessness, the G20 said.

In addition to the regulatory reforms, which are supposed to be developed by the end of 2010 and put in place two years later, the G20 took aim at lavish pay packages for bankers, although it was unclear whether the agreed measures would establish a firm cap on compensation.

The G20 leaders also agreed to shift some voting power at the International Monetary Fund to underrepresented countries such as China from rich ones, another sign that the developed world had accepted the shifting balance of economic power.

In the statement, the G20 endorsed a plan to phase out fossil fuel subsidies as a way to combat global warming, and to step up efforts to complete the Doha round of trade talks.

REBALANCING GROWTH

World leaders also backed a U.S.-led push for reshaping the global economy to smooth out huge surpluses in exporting powerhouses such as China and large deficits in big importing countries such as the United States.

Obama wants the United States to break out of its borrow-and-spend mould and embrace saving and investment, but that means countries such as China that rely on exports for growth must also adjust.

G20 leaders agreed to work together to assess how their domestic policies mesh and to evaluate whether they are collectively consistent with more sustainable and balanced growth.

Kept at a distance from the G20 convention centre, about 10,000 protesters marched against capitalism and the G20's agenda, some of them chanting You're sexy, you're cute, take off that riot suit to the police.

There was only one arrest on Friday and the mood was buoyant, in stark contrast to protests on Thursday when there were clashes with police and dozens of arrests.

(Reporting by Reuters G20 team; Additional reporting by Richard Leong in New York; Writing by Emily Kaiser; Editing by Frances Kerry)