The shilling fell as low as 87.50 to the dollar, the weakest level since Jan. 12 but still just off its 2012 low hit in the first week of the year. At 0630 GMT, it was trading just off the session low at 87.35 to the greenback.

"There is a mismatch of demand and supply," said Dickson Magecha, a trader at Standard Chartered. "Banks are short covering because customers are panic buying. They want to lock in before it goes higher."