President Donald Trump on Sunday strenuously defended US efforts to bring relief to storm-battered Puerto Rico, even as one island official said Trump was trying to gloss over "things that are not going well."

A day after Trump launched a Twitter attack against San Juan Mayor Carmen Yulin Cruz following her desperate pleas for more help, he tweeted that "we have done a great job with the almost impossible situation in Puerto Rico."

Trump said US military teams and the Federal Emergency Management Agency were doing "amazing work" and credited the island's governor and others with a "fantastic job."

But two weeks after devastating Hurricane Maria left much of the island without electricity, fresh water or sufficient food, many Puerto Ricans seemed to have a far gloomier outlook.

Hilda Lopez, in her 80s, broke into tears when approached as she left Mass at San Juan's Cathedral.

"Never has our enchanted island been in the dark and with so much suffering," she said between sobs, a green shawl draped over her shoulders.

"It pains me that the president of the United States has expressed himself the way he has in recent days. I don't know if it's because he doesn't appreciate the pain" that Puerto Ricans are suffering.

Trump, in one tweet Sunday, said that those who continued to criticize the relief effort were either "Fake News or politically motivated ingrates."

Mayor Cruz, in an interview with CNN, shrugged off the criticism. She told CNN that millions were still in dire circumstances, and that Trump seemed to be "looking for an excuse for things that are not going well."

Trump's criticism has drawn sharp retorts even from within his Republican Party.

"When people are in the middle of a disaster, you don't start trying to criticize them," Ohio Governor John Kasich, a presidential hopeful in 2016, said on CNN. "You got to be bigger than the nonsense."

And Senator Bernie Sanders, an independent who ran for the Democratic presidential nomination in 2016, told CNN: "Speaking from his fancy golf club, playing golf with his billionaire friends, attacking the mayor of San Juan, who is struggling to bring electricity to the island, food to the island, water to the island, gas to the island, that is just -- it is unspeakable.

"And I don't know what world Trump is living in."

Trump spent Sunday morning at his golf resort in Bedminster, New Jersey, before traveling to another golf course in nearby Jersey City to present the trophy to the winner of the Presidents Cup tournament.

The Trump administration sent several top officials onto Sunday talk shows with the message that the relief effort is going well, despite complaints that the federal effort in Puerto Rico has fallen short of the work done after hurricanes ravaged Texas, Florida and Louisiana.

"The administration's done an extraordinary job of delivering goods and services to people," said White House economics adviser Gary Cohn, appearing on Fox News Sunday. "We're working full-speed ahead."

FEMA administrator Brock Long offered a slightly more cautious assessment, telling ABC's "This Week" that "we've got a long way to go."

"We're finding success in some areas, and in some areas we see setbacks" he said, "but we are making progress."

FEMA has been under heavy duress since successive hurricanes pounded the US Gulf Coast and devastated parts of the Caribbean starting six weeks ago.

Long said the storms that struck Puerto Rico -- Irma and Maria -- greatly magnified the challenge for relief workers by damaging or wiping out some 3,200 roads or bridges.

Still, he said, "We (have) pushed everything into that island that we can."

The US Defense Department meanwhile reported that it was continuing efforts to bring relief even to the most isolated communities, while repairing roads, ports and electrical networks, and reinforcing the badly eroded Guajataca dam. Only one-tenth of the island has cell service.

The Pentagon said 59 of 69 hospitals surveyed were partly or fully operational. The navy hospital ship Comfort is scheduled to arrive in San Juan on Wednesday.

When Long was asked about Trump's suggestion that Puerto Ricans wanted "everything to be done for them," he said, "I believe the Puerto Ricans are pulling their weight."

But he suggested that Mayor Cruz might not be aware of all that FEMA is doing because she had visited the agency's joint field office in San Juan only once.

Asked about that on ABC, Cruz said that after that visit "we have been communicating ever since."

Trump is scheduled to visit the island on Tuesday. Would Cruz be willing to meet with him?

"If he asks to meet with me," she said, "of course I will meet with him."

Outside San Juan Cathedral on Sunday, 57-year-old retiree Aida Rosario said she, too, would welcome a Trump visit.

"Let Trump come, let him see how things are here, let him experience what we are living," she said.

"There are people who can hardly eat -- or maybe once a day...

"We are in difficult times."