Pepco was the target of growing fury Monday as more than 200,000 of the utility’s customers endured their third full day without electricity in the wake of Friday’s fast-moving storm that ravaged power systems and forced millions to suffer through an unforgiving heat wave without air conditioning.

“They need to move faster,” D.C. Mayor Vincent Gray said. “Pepco’s pace at restoring power, to me anyway, is unacceptable, and the speed of their response has been disappointing.”