CAIRO, Aug 30 (Reuters) - Egypt's central bank held the pound steady against the dollar at its regular foreign currency sale on Tuesday as the currency weakened slightly on the black market.

The bank sold $119.2 million at an unchanged rate of 8.78 per dollar.

Egypt is facing an acute dollar shortage that sent its foreign reserves down to $15.5 billion in July, near a critical level that would cover only three months of imports.

A widening gap between official and black market rates for the dollar has increased pressure to devalue the currency. Two black market traders cited a selling range of 12.70-12.75 pounds per dollar on Tuesday, weaker than last week's range of 12.50-12.65 pounds. They gave no indication of trade volumes.

Egypt has reached an agreement with the International Monetary Fund over a $12 billion three-year lending programme that it hopes will plug the nation's funding gap and restore market confidence, encouraging investment that could help to ease the currency crunch. (Reporting by Asma Alsharif; Editing by Dominic Evans)