President Trump is coming under intense criticism from Democrats and Puerto Rico officials over his morning tweet saying that emergency personnel can't stay in the U.S. territory forever.

Early Thursday, Trump tweeted about Puerto Rico, saying, "we cannot keep FEMA [the Federal Emergency Management Agency], the Military & the First Responders, who have been amazing (under the most difficult circumstances) in P.R. forever!" The comment drew a swift rebuke from lawmakers, who accused Trump of abandoning the island's residents, who are American citizens, as they continue to recover in the wake of Hurricanes Irma and Maria.

"It is shameful that President Trump is threatening to abandon these Americans when they most need the federal government’s help," said House Minority Whip Steny Hoyer (D-Md.) in a statement.

"He has a responsibility to our fellow citizens in Puerto Rico and on the U.S. Virgin Islands to ensure that every federal resource is made available to assist in recovery and rebuilding for as long as it takes," added Hoyer.

Congressional Hispanic Caucus Chairwoman Rep. Michelle Lujan Grisham (D-N.M.) said Trump is "failing to live up to his responsibility to the American people."

"His suggestion that we will cut and run on our fellow Americans is disgraceful. The President of the most powerful and wealthiest country in the world should be assuring devastated Americans that its government's response will be unrelenting and unequivocal in restoring water, food, electricity, and critical healthcare and infrastructure, not the opposite,” said Lujan Grisham in a statement.

"Mean tweets completely contrary to Pence & GOP pledges!," she tweeted

Ryan said Wednesday it's "critical" that the House pass a $36.5 billion relief bill that's up for a vote Thursday . That bill would fund recovery for Texas, Florida, Puerto Rico and the Virgin Islands, all hit by hurricanes in August and September.

ADVERTISEMENT But Trump singled out Puerto Rico, a U.S. territory that was struggling with managing $72 billion in debt before being hit by the two hurricanes.

Hurricane Maria hit Puerto Rico especially hard, crippling its already-weak infrastructure. The island's dilapidated power grid was almost entirely wiped out, leaving millions without power.

Power has been restored to only 17 percent of the island's 3.5 million residents, and authorities have warned that it could take up to a year to fully reestablish the power grid.

Puerto Rico's infrastructure deficiencies are linked to the island's massive debt. The territory's power utility, PREPA, has $9 billion in unpaid debt.

Trump quoted journalist Sharyl Atkisson in his tweets Thursday , saying, "Puerto Rico survived the Hurricanes, now a financial crisis looms largely of their own making."

House Minority Leader Nancy Pelosi (D-Calif.) called Trump's tweets "heartbreaking."

"It’s heartbreaking and it lacks knowledge — knowledge about what the role is for FEMA and the others in time of natural disaster [and] what our responsibility is as the federal government to the people of our country," said Pelosi at her weekly press conference.

FEMA Administrator Brock Long said Monday the agency's role is not as a first responder, and that its reconstruction role in Puerto Rico — particularly in terms of the power grid — would be unique in that restoring infrastructure to its unsound pre-storm conditions would be counterproductive.

FEMA recovery efforts can last months or years, depending on the level of damage and the amount of reconstruction required.