G-20 summit begins

LONDON (CNN) -- Leaders attending the G-20 summit in London Thursday said they were confident and hopeful of progress as they sat down to grapple with the global economic crisis.

"There is a great degree of convergence, so I am very confident about the result of the summit today," European Commission President Jose Manuel Barroso told CNN Thursday morning.

"Important to get a good outcome," Australian Prime Minister Kevin Rudd said on Twitter.

British Business Secretary Peter Mandelson told CNN there are some "strains" among the delegates, "but I hope very much that they will be ironed out and we'll come out with agreement at the end of the day."

The leaders say they want to find ways to stabilize financial markets throughout the world and pull the world out of a deepening recession.

They sat at the table Thursday for their first plenary session with several targets in their sights, including tax havens and protectionism.

French Finance Minister Christine Lagarde called for a firm stand on tax havens, wrote Stephen Timms, the financial secretary to the British Treasury, from the summit.

"We have to be clear that those that want to keep shadow banking systems that are kind of underground (with) clandestine finances have to suffer sanctions, because it's once again a problem of confidence," Barroso said. "We are for open economies and open markets, but open economies and open markets have to respect some rules."

Britain will push for the same regulation of banks and financial institutions that operate in a "shadow banking world," Mandelson said. He said an international body should oversee the regulation.

Leaders will also be pushing for more fiscal stimulus.

British Prime Minister Gordon Brown is arguing for world leaders to maintain their investments and fiscal stimuli while also giving more money to institutions like the International Monetary Fund, Mandelson said.

The IMF can then deliver those resources to poorer countries and emerging economies, he said.

"They are becoming major drivers of growth in the global economy," Mandelson said of those countries. "So we want a strong commitment, a hefty infusion of resources."

Barroso and Mandelson called for concrete commitments on the economy. French President Nicolas Sarkozy indicated this week that if the summit's final communique fails to contain strong language and clear steps, he may even walk out of the meeting.

Sarkozy and German Chancellor Angela Merkel said Wednesday they can accept debate and negotiation as long as firm steps are taken in the end.