Former Federal Reserve chairman Alan Greenspan says the United States' debt ceiling crisis is far from over and the eurozone needs political union to survive.
Mr Greenspan ran the Federal Reserve between 1987 and 2006.
He says a repeat of the crisis that brought the US close to default is perfectly conceivable.
In a wide-ranging interview with the BBC, Mr Greenspan said that the euro bloc needs to consolidate politically if its economy is to recover long-term.
"The culture of Greece is not the same as the culture of Germany, and to fuse them into a single unit is extremely difficult. The only way you can do it is by political union.
Mr Greenspan has released a new book, The Map and the Territory.
