With federal aid only trickling in, many Puerto Ricans have already started their own cleanup operations, with some small shops and restaurants reopening with the help of generators.

But long lines remain at supermarkets and gas stations — with water, gas and ice all rationed.

“We need to prevent a humanitarian crisis occurring in America. Puerto Rico is part of the United States. We need to take swift action,” Rossello said at a press conference in the capital San Juan, warning there could be a “massive exodus” of people from the island.

“The magnitude of this hurricane and the two we passed is unprecedented,” he added, pointing out that Puerto Rico is already in a dire economic situation, with government debt surpassing $70 billion.

After facing blistering criticism for focusing much of his attention in recent days on a bitter feud with NFL players instead of the ravaged US territory, President Donald Trump acknowledged that Puerto Rico was “in deep trouble.”

“Texas & Florida are doing great but Puerto Rico, which was already suffering from broken infrastructure & massive debt, is in deep trouble,” he tweeted.

“It’s old electrical grid, which was in terrible shape, was devastated. Much of the Island was destroyed, with billions of dollars owed to Wall Street and the banks which, sadly, must be dealt with. Food, water and medical are top priorities – and doing well. #FEMA.”

Hurricanes Maria and Irma killed 13 people on the island — with Maria almost completely destroying telecommunication networks.

“We got a lot of work to do, we realize that,” US Federal Emergency Management Agency (FEMA) chief Brock Long said, speaking alongside Rossello, adding that the agency is “working around the clock” to repair crucial infrastructure and save lives.

Homeland Security Advisor Thomas Bossert said he had seen “great devastation” on the island, promising locals “what you need to recover.”

The White House denied it had been slower to act following Hurricane Maria in overwhelmingly Hispanic Puerto Rico than in the aftermath of Hurricanes Irma and Harvey on the US mainland.

“We’ve done unprecedented movement in terms of federal funding to provide for the people of Puerto Rico and others that have been impacted (by) these storms,” said spokeswoman Sarah Huckabee Sanders.

“We’ll continue to do so and continue to do everything that we possibly can under the federal government to provide assistance.”

– ‘Wholly inadequate’ -But Representative Adam Smith, the top Democrat on the House Armed Services Committee, condemned the Trump administration’s response to the crisis as “wholly inadequate.” 

“A territory of 3.5 million American citizens is almost completely without power, water, food and telephone service, and we have a handful of helicopters involved in DOD’s response. It’s a disgrace,” he said.

The five living former US presidents extended their “One America Appeal” — set up in the wake of Hurricanes Harvey in Texas and Irma in Florida — to help with the devastation in Puerto Rico.

“Many houses have no roof, and many trees and electricity poles are on the ground,” said Angel Marcano, 45, a social worker in the La Perla neighborhood, where Puerto Rican singer Luis Fonsi performed in the video for his summer hit “Despacito.”

“I was afraid, I was worried, I lost my cool — but now we have to roll up our sleeves and work to restore the neighborhood and the communities,” Marcano said.

Returning from a trip to the island, Florida Senator Marco Rubio warned: “Tremendous damage. Potential for serious crisis in areas outside of #SanJuan MUST get power crews in ASAP.”

Engineers say it could take months for power to be fully restored in Puerto Rico.

After Hurricane Harvey hit Texas, Trump traveled to the state twice in one week.

He also traveled to Florida after Irma, handing out sandwiches and stressing that restoring electricity was a priority.

Trump spoke to Puerto Rico’s Governor Ricardo Rossello and the governor of the US Virgin Islands by phone over the weekend, and vowed to visit both places — although no date has yet been set. DM