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The worst of the global financial crisis is yet to come and a large U.S. bank will fail in the next few months as the world's biggest economy hits further troubles, former IMF chief economist Kenneth Rogoff said on Tuesday.

"The U.S. is not out of the woods. I think the financial crisis is at the halfway point, perhaps. I would even go further to say 'the worst is to come'," he told a financial conference.

"We're not just going to see mid-sized banks go under in the next few months, we're going to see a whopper, we're going to see a big one, one of the big investment banks or big banks," said Rogoff, who is an economics professor at Harvard University and was the International Monetary Fund's chief economist from 2001 to 2004.

"We have to see more consolidation in the financial sector before this is over," he said, when asked for early signs of an end to the crisis.