LONDON -- Billionaire investor George Soros said on Thursday G20 leaders had taken decisive action to combat the worst economic crisis since the Great Depression of the 1930s.

"This could well be a turning point because the authorities got together and they have taken the steps," Soros said in an interview on BBC television.

The investor, who said last week that the G20 meeting in London would be a "make or break event" for global markets, added: "I think it has definitely made it."

World leaders clinched a $1.1 trillion deal to boost the global economy and said financial rules would be tightened to prevent a repeat of the crisis.

Hungarian-born Soros said the leaders had "anticipated there is a very serious problem facing the developing world."

"If it hadn't been addressed today, we would have another very serious deterioration in what I call the periphery countries, including Eastern Europe. They have definitely prevented it by the measures they have taken," he said.