The Group of 20 approved a greater voice for Asian and Latin American countries in a historic shift that recognises the rising influence of both regions.

The leaders of the world's 20 largest economies were attending a two-day meeting dedicated to fostering a healthy global recovery, and European leaders were expected to secure a priority of their own: limits on bankers' bonuses.

But the economic developments were overshadowed on Friday by the disclosure of a secret Iranian nuclear facility. President Barack Obama, French President Nicolas Sarkozy and British Prime Minister Gordon Brown appeared together to demand that Iran fully disclose its nuclear ambitions and threatened new sanctions.

The decision to raise the profile of the G-20 represents a major change and underscores how the world's balance of power has shifted in the last 40 years.

board of directors

The leaders decided the G-20 will serve as the board of directors on global economic cooperation, a function that for more than three decades had been performed by a smaller club: the United States, Japan, Britain, Germany, France, Italy, Canada and later Russia. The G-20 includes such developing economies as China, Brazil and India.

The G-8 will, however, continue to meet on matters of common importance such as national security, the White House said last Thursday.

The Pittsburgh meeting marked the third G-20 leaders summit in less than a year as the countries continued to grapple with a debilitating downturn that has resulted in millions of unemployed around the world, the loss of trillions of dollars in wealth and massive amounts of government stimulus spending designed to jump-start economic growth.

The leaders trickled into Pittsburgh throughout last Thursday - most of them in from New York, where they attended the opening of the United Nations General Assembly. Later, they gathered with their spouses for a welcoming reception at a botanical reserve before parting for separate banquets Thursday night.

Less than one mile (two kilometres) away, protesters seeking to show unhappiness with global capitalism clashed with police who fired canisters of pepper spray and rubber bullets at several hundred demonstrators who had tried to march towards the convention centre.

According to Pittsburgh police, 24 people were arrested during the day and another 42 people were arrested overnight. Police said six people were treated for injuries and other medical problems, including heat exhaustion and reaction to pepper spray.

With spreading signs that the worst of the downturn is over and many countries beginning to return to modest growth, the leaders were able to hold their discussions with less of a crisis atmosphere than their two previous meetings - in November in Washington and in April in London.

But the lessening of the crisis raised concerns that the momentum to implement reforms could lessen as well, posing a threat G-20 officials vowed to resist.

US Treasury Secretary Timothy Geithner cited progress on several fronts, most notably the bankers' salaries issue, with strong support from France and Germany. EU leaders had called for links between bankers' pay and the companies' long-term performance and have sought to end bonuses where a banker is paid a set amount regardless of the risk being taken.

Geithner said the G-20 countries had reached a consensus on the "basic outline" of a proposal to limit bankers' compensation by the end of this year. He said it would involve setting separate standards in each of the countries and would be overseen by the Financial Stability Board, an international group of central bankers and regulators.

European Commission President José Manuel Barroso again pressed for the limits.

"Europeans are horrified by banks, some reliant on taxpayers' money, once again paying exorbitant bonuses," Barroso said. "It is important we take action."

link the pay to risks

China planned to link the pay of bankers to risks taken by their institutions but was not looking at salary caps, a government spokeswoman in Beijing said.

Geithner predicted the proposed crackdown on bankers' bonuses would be in place by the end of the year.

German Chancellor Angela Merkel said she was optimistic that far-reaching agreements were possible in Pittsburgh. She warned against focusing too much on imbalances in the world economy, but added, "I think we have a chance to reach progress in all important fields."

Geithner also said summit partners would endorse the broad outlines of a proposal, supported by Obama, to deal with huge imbalances in the global economy - such as large trade surpluses in China and record budget deficits in the US.

He then reached out to China and said the US supports the Asian country's efforts to gain greater voting rights in the International Monetary Fund over the reservations of European nations, who would lose influence.

Given the rise of China's economic powers, "it's the right thing," and Europe recognises that, Geithner said.

The summit ended on Friday with a joint communiqué likely to paper over many remaining disagreements.