By 10 a.m. Eastern on Thursday, the outages had declined from of all cell sites in the region a day earlier, the FCC said in a statement on Thursday afternoon. That was an average across the area most affected by the storm, stretching across parts of 10 states. In addition, cable TV and cable Internet outages had been reduced to about 12 percent to 14 percent, the agency said.

"Overall, we're seeing both continued improvement in communications networks and also that much work remains to be done to restore service fully," FCC Chairman Julius Genachowski said in the statement. As a key part of the recovery effort, the agency is working with federal, state and local authorities to help get fuel to generators, he said.

There was steady improvement in the wired and wireless communications networks across the storm area, but restoration of service in the areas hardest hit, such as New York and New Jersey, has been more difficult, said David Turetsky, head of the FCC's Public Safety & Homeland Security Bureau. Some sites that could otherwise have come back online were held back by failures elsewhere in the communications infrastructure, he said.

The FCC said its Disaster Information Reporting System (DIRS) remained active and the agency was still collecting data from carriers about the effects of the storm.

Emergency 911 calls are being received throughout the storm-affected area, though in some cases they are being re-routed to other 911 centers or don't contain location information, the FCC said.