President Donald Trump on Thursday partly blamed Puerto Rico's devastation on the island itself, saying the federal government cannot keep emergency responders in the U.S. territory "forever."

Puerto Rico Gov. Ricardo Rossello later tweeted that "U.S. citizens in Puerto Rico are requesting the support that any of our fellow citizens would receive." San Juan Mayor Carmen Yulin Cruz, a frequent Trump critic, wrote that the president was "incapable of fulfilling the moral imperative" to help Puerto Ricans, adding, "Shame on you!"

She said Trump's comments seem to be coming from "a Hater in Chief."

@POTUS your comments about Puerto Rico are unbecoming of a Commander in Chief they seem more to come from a "Hater in Chief".

Hurricane Maria slammed into Puerto Rico on Sept. 20, causing widespread destruction. Three weeks later, more than 80 percent of the island remains without power, and many residents still lack access to clean drinking water. At least 45 people in the territory have died.

In a series of tweets Thursday morning, Trump pinned some of those problems on Puerto Rico. Puerto Rico "survived the hurricanes, now a financial crisis looms largely of their own making," he wrote, quoting Sharyl Attkisson, a host for right-leaning Sinclair Broadcast Group.

"A total lack of accountability say [sic] the Governor. Electric and all infrastructure was a disaster before hurricanes. Congress to decide how much to spend," Trump continued. "We cannot keep FEMA, the Military & the First Responders, who have been amazing (under the most difficult circumstances) in P.R. forever!"

Trump 1: "Puerto Rico survived the Hurricanes, now a financial crisis looms largely of their own making." says Sharyl Attkisson. A total lack of.....

Trump 2: ...accountability say the Governor. Electric and all infrastructure was disaster before hurricanes. Congress to decide how much to spend....

Trump 3: ...We cannot keep FEMA, the Military & the First Responders, who have been amazing (under the most difficult circumstances) in P.R. forever!

Trump's comments follow Vice President Mike Pence's pledges of support to the people of Puerto Rico last week.

Touring the island on Friday, Pence said the Trump administration would be "here for the long haul," according to The Associated Press. He told the island's residents that he had "faith in President Trump's leadership, his determination to stand by Puerto Rico in this challenging time."

In response to Trump's comment, Senate Minority Leader Chuck Schumer tweeted: "There is still devastation, Americans are still dying. FEMA needs to stay until the job is done." He accused Trump of treating Puerto Ricans "differently than other Americans when it comes to natural disasters."

Schumer: Why do you continue to treat Puerto Ricans differently than other Americans when it comes to natural disasters?

The House could vote as early as Thursday on a $36.5 billion bill to provide relief funding for recent hurricanes and wildfires raging in California.

Asked about Trump's tweets on Thursday, House Speaker Paul Ryan said the federal personnel in Puerto Rico right now are "necessary" amid a "humanitarian crisis." He added that the federal government needs to make sure the island can "rebuild its economy and be self-sufficient."

Trump has faced criticism for an apparent lack of empathy for Puerto Rico amid the disaster response. In previous tweets, he urged Puerto Ricans to do more to help the recovery and called those criticizing the federal response "politically motivated ingrates."

Over the weekend, he tweeted that "nobody could have done what I've done" for Puerto Rico "with so little appreciation."

During a trip to the island last week, Trump said the hurricane destruction had thrown his administration's budget "a little out of whack." Later that day, he tossed packages of paper towels to hurricane victims.

On top of the humanitarian crisis, the federal government has to figure out how to handle Puerto Rico's more than $70 billion in debt. Trump previously suggested he could wipe out the obligations, though the White House has walked back that statement.