Mayor Vincent C. Gray added his voice Monday to the list of leaders around the region angered by power outages and Pepco’s slow restoration of electricity.

Gray, who was wrapping up a trade mission to China during Friday’s storm, returned to a city forced to close recreation centers and schools because of the outages and on a personal note, a Hillcrest home with no power.

Mayor Vincent Gray speaks at a news conference on Capitol Hill, on May 29. (J. Scott Applewhite/AP)

“While I want to thank them (Pepco) for their progress, they need to move faster,” Gray said at a news conference at the city’s command center in Southeast. “How many times have we been through this before? . . .Friday is just not good enough.”

More than 40,000 District customers remained without power as of Monday afternoon, Gray said. “I think people are fed up with power outages. We need a game changer,” he said.

The current situation has renewed discussion about burying powerlines, he said. Gray said he has heard cost estimates in the billions of dollars. He said he does not have any specific answers yet and will need to discuss Pepco issues with Gov. Bob McDonnell and Gov. Martin O’Malley. He said he is sure of one thing: “This will happen again.”

Gray was flanked by several city officials who presented a laundry list of problems from downed trees to non-working traffic signals to school and recreation closings.

Crews have worked around the clock cutting downed trees so much so that chainsaws have broken, Gray said. The city has purchased more than a half dozen chainsaws in an emergency procurement, he said.

Meanwhile, 65 traffic signals are not functioning, which could present a problem on July 4 when hundreds of thousands of people are expected to descend on the National Mall for festivities, including the fireworks display. “The Fourth of July is still on,” police Chief Cathy L. Lanier said.

Police officers had already been placed on 12-hour shifts, and they are being supplied with water to get through the heat, Lanier said. “It’s tough conditions, but they are making it through just fine.”

D.C. Public Schools shut down summer school Monday and will again Tuesday, affecting about 6,000 students. Another 1,500 participants in the Summer Youth Employment Program did not report to work on Monday and will not report on Tuesday because of outages that closed their work sites.

Five libraries — Martin Luther King Jr. Memorial, Anacostia Neighborhood, Tenley-Friendship, Dorothy I. Height/Benning Neighborhood and William O. Lockridge/ Bellevue — will stay open until 9 p.m. Monday to serve as cooling centers for residents.

Hours at several pools and recreation centers that have power are also being extended to help residents cool off, city officials said.