The leaders of the world's biggest economies head to Pittsburgh today promising tough action to police financial markets and prevent a repeat of last year's crash.
'In Pittsburgh, we will work with the world's largest economies to chart a course for growth that is balanced and sustained,' US President Barack Obama told the United Nations on the eve of the G20 summit.
'And that means strengthening regulation for all financial centres, so that we put an end to the greed, excess and abuse that led us into disaster, and prevent a crisis like this from ever happening again,' he added.
The two-day meeting - grouping the world's 19 biggest developed and emerging economies plus the European Union - comes just over a year after a US credit market collapse unleashed global economic chaos.
Read a full list of summit participants here
It also comes six months after the same G20 chiefs met in London to coordinate their response to the crisis, and their performance in Pittsburgh will be judged on whether they have lived up to their earlier promises.
Summit delegates all vow to take tough and lasting measures to bring order back to the markets, shore up failing institutions, save jobs and rekindle growth, but each arrives in Pittsburgh with their own priorities.
French President Nicolas Sarkozy said this week he would push his partners to impose sanctions on uncooperative tax havens starting next year.
Last week, France and Germany pressed for caps on bankers' bonuses, amid opposition from Britain and the US, but a watered-down compromise deal appears likely to be reached, officials said.
Green subsidies on G20 agenda
Obama, hosting his first global summit, also sought to convince developing and developed nations to agree on a plan to phase out subsidies for the fossil fuel industries that are blamed for global warming.
The proposal might be welcomed by the environmental protesters picketing Congress, a Greenpeace adviser said, but it won't replace the need for Obama to show leadership on the struggle to agree on a global climate deal.
Emerging economies, led by India, want billions of dollars in subsidies from the developed world to help them convert to greener technologies if they are to sign up to a deal at a key climate summit in Copenhagen in December.
Britain's Prime Minister Gordon Brown was the first leader to put a figure on such aid - suggesting $100 billion by 2020 - and he said that he would push the G20 for action.
Aside from financial regulation and climate change, the summit is also expected to discuss when and how to begin scaling back the multi-trillion dollar stimulus packages countries established to fight the recession.
Japan and continental Europe have begun to edge out of the slump and are starting to look at cuts, but others feel such a move would be premature.
The summit is being held against the backdrop of a city that once faced ruin with the collapse of the regional steel industry, but has reinvented itself as a hub of high-technology industries.
