SAN JUAN, P.R. — A surge of fuel and food supplies and federal government personnel has begun to arrive in Puerto Rico, the governor of the storm-battered island said Sunday morning.

Gov. Ricardo A. Rosselló told reporters that over the next two days, more than half a million barrels of diesel fuel and nearly a million barrels of gasoline would reach Puerto Rico. The fuel is badly needed to power emergency generators and to distribute food and other supplies across the island.

Mr. Rosselló said that the Defense Department had increased its footprint on Puerto Rico to 6,400 people, from roughly 4,600 two days earlier, with more coming, and that other federal agencies were also sending more staff to aid in the island’s recovery from Hurricane Maria, which smashed through the island on Sept. 20.

The Trump administration’s response to the disaster has become a heated political issue. Some Puerto Rican officials, including the mayor of San Juan, Carmen Yulín Cruz, have made televised pleas for a faster and more robust response. Others, like the governor, have spoken more positively about federal efforts.

For his part, President Trump has tweeted that “the Fake News” and “politically motivated ingrates” were distorting the picture of what he maintained was an effective response to the storm.

On Sunday morning, Mr. Trump tweeted that his administration had “done a great job with the almost impossible situation in Puerto Rico.” The president also wrote, “All buildings now inspected … for safety,” but offered no basis for the statement.

The assertion seemed to surprise Mr. Rosselló. “All buildings?” he said. “I’m not aware of such inspection. Of course, there are areas of Puerto Rico which we haven’t really gotten in contact. Perhaps he was referring to a particular set of buildings. I’m not sure.”

Life remains far from normal on the island, 11 days after the storm made landfall. The electricity system was devastated, and it could be months before residents get back regular electric service. The governor said that more than 720 of the island’s 1,100 gas stations had reopened, but there are still shortages and distribution problems. Some stations in San Juan had short lines of customers on Sunday, but others in outlying areas were still choked with lines that stretched hundreds of cars long.

According to a Puerto Rican government website tracking the recovery, 11 percent of cellphone towers are working, and 5 percent of the electric grid. Authorities said that 46 of the island’s 48 dialysis centers were operating, using diesel-fueled generators. Nine hospitals now have regular electricity service restored, and dozens more are running on generator power.

Gov. Rosselló was asked what else was needed to get Puerto Rico through the emergency.

“People, which we’re getting,” he said. “Resources, which we’re getting. And fine-tuning the logistics of a new logistical system in Puerto Rico, because the roads have been decimated.”