Developing nations' borrowing costs jumped to the highest in six years as Belarus joined governments seeking a bailout from the International Monetary Fund to help weather the credit crisis and slump in commodities.

The extra yield investors demand to own emerging-market government bonds instead of US Treasuries rose 24 basis points to 8.26 percentage points, the most since November 2002, according to JPMorgan Chase & Co's EMBI+ index.

The annual cost to protect Russia's bonds from default soared to 10.5 percent of debt insured, from 9.5 percent on Tuesday, according to credit-default swap prices from CMA Datavision.