(AP)—Federal regulators say wireless networks are inching back into operation in areas hit by Sandy, as carriers struggle to replenish diesel tanks at backup generators.

The says 19 percent of in a storm-ravaged area stretching from Virginia to Massachusetts are still out of operation Thursday. That's down from 25 percent Tuesday.

Many cell towers have generators, but as they run low on fuel, refilling them "is a particularly critical challenge," says David Turetsky, head of public safety at the FCC.

Cable connections have come back up faster. The agency now estimates that 12 to 14 percent of cable-connected households are still out, down from 25 percent on Tuesday.