In one significant step, leaders of the Group of 20 major economies agreed to strengthen the resources of the International Monetary Fund to better battle financial crises like the one now buffeting Europe.

Summit host, French President Nicolas Sarkozy, acknowledged the grim mood at the two-day summit - as fears grow of another major recession.

Sarkozy said G20 members were committed to using every tool to sustain world growth.

The financial problems of Italy and Greece dominated the summit, which took place as the government of Greek Prime Minister George Papandreou teetered on the edge.

Italy agreed to allow the IMF to monitor whether the government implements an ambitious austerity package. IMF chief Christine Lagarde was blunt at a press conference, as she described international doubts.

Non-European members at the summit have urged the Europeans to speedily resolve the eurozone crisis. US President Barack Obama said he is confident they can do so.

Among other measures, the G20 leaders agreed to toughen capital requirements for banks - naming 29 top banks on the list - so taxpayers do not end up bailing out those that go under. The group also vowed to crack down on tax havens and consider new sources of development assistance for poorer nations.