But some disaster experts say that while the military can be useful, it is not a cure-all in relief efforts, and that too many troops could overwhelm available resources in Puerto Rico. Others note the demands of addressing three major hurricanes in a row. The Trump administration has put an Army general in charge of recovery efforts and several thousand additional troops will soon be sent to the island.

In a conference call with reporters on Tuesday, government officials said they were making progress in aid efforts.

Alejandro De La Campa, the coordinating officer for the Federal Emergency Management Agency in Puerto Rico, said officials so far have installed 22 generators, primarily at high-priority facilities such as hospitals and nursing homes. The Army Corps of Engineers is deciding where to install 100 additional generators, and another 300 are en route to the island. Officials said about $28 million had been approved for local municipalities for debris removal and other services.

Still, Mr. De La Campa said, recovery efforts in the interior of the island continue to lag because many of the roads remain inaccessible.

Image The contents of a food box from FEMA. Credit... Erika P. Rodriguez for The New York Times

“We are currently developing a strategy to reach the center of the island,” he said.

FEMA officials said they did not encounter the same issues distributing supplies to residents after the hurricanes in Texas and in Florida because, despite the damage, most roads into those areas remained intact. Once the floodwaters receded they were able to deliver aid.