A Marine helicopter arrives at Isla Grande Airport in San Juan, Puerto Rico, on Sept. 29. (Dennis M. rivera Pichardo/For The Washington Post)

The Trump administration is preparing to ask for at least $10 billion more in federal relief for disaster recovery in the wake of the latest deadly hurricane to strike U.S. shores, according to multiple people familiar with the plans.

The White House is expected ask for another short-term infusion of cash to pay for the response to the damage caused by Hurricane Maria across Puerto Rico and the U.S. Virgin Islands, according to top congressional aides. In the case of Puerto Rico, officials there and some lawmakers on the mainland are clamoring for legislation that would provide tens of billions of dollars in relief and address Puerto Rico’s long-simmering fiscal crisis, shore up its bankrupt electric company and plug a shortfall in Medicaid funding. Work on a more comprehensive relief package will continue into the fall, the aides said.

“This is a disaster, this is something that calls for a plan. You can call it the Marshall Plan or the Trump Plan, but there has to be a plan,” said Puerto Rico State Sen. Carmelo Ríos. “There has to be a plan to make sure that this kind of event doesn’t happen again.”

Ríos and other legislators from Puerto Rico and the Virgin Islands arrived in Washington on Monday for meetings with top agency officials and senior lawmakers about forthcoming relief plans. A planned event on Capitol Hill to draw attention to their campaign for a robust relief package was canceled because of the mass shooting in Las Vegas.

Ríos, the Puerto Rico Senate’s majority leader, warned that Congress should act quickly. If it doesn’t, he expects 100,000 to 200,000 island residents to relocate, at least temporarily, to the mainland United States in the coming weeks.

Parishioners pray as church services resumed at a hurricane-damaged church in Caonillas, Puerto Rico, on Oct. 1. (Michael Robinson Chavez/The Washington Post)

“They’re not going to Florida, only. They’re going to Texas, to Pennsylvania, to North Carolina — I have a lot of friends going there — because they’re looking for places where they can settle,” Ríos said.

In response to the impending influx of Puerto Ricans, Florida Gov. Rick Scott declared a state of emergency in all of the state's 67 counties on Monday so that local and state agencies can begin preparing to provide services.

“With families displaced by Hurricane Maria already present and still arriving in Florida, it is critical that our state is prepared to provide the resources they need upon entering our state,” Scott (R) said in a statement.

At the White House, press secretary Sarah Huckabee Sanders didn’t say when the administration will be asking for more federal funding, but she defended the administration’s ongoing response, saying, “The federal government is doing everything within our powers and capabilities to first focus on the life-sustaining and lifesaving measures, as well as on the rebuilding process.”

President Trump, who clashed via Twitter with some Puerto Rican officials over the weekend, is slated to visit the island on Tuesday and is expected to meet with first responders and storm survivors.

Congress approved $15.25 billion in federal relief last month to pay for recovery operations after hurricanes hit Texas and Florida. As of Monday, the Disaster Relief Fund, operated by the Federal Emergency Management Agency, still had about $9.4 billion, the agency said. But the response to storms in Texas and Florida has now been compounded by the devastation across Puerto Rico and the U.S. Virgin Islands, and officials expect the fund to be depleted in the coming weeks.

A political party banner waves over a home damaged by Hurricane Maria, in Toa Baja, Puerto Rico, on Oct. 2. (Ramon Espinosa/AP)

The slow pace of response by the administration is frustrating some Democrats, who were hoping to learn by this week how much more money may be needed for temporary relief. But they said they were not provided specific estimates during a meeting Monday.

“There is no dollar estimate for what is needed, because there is no plan in place,” said Sen. Elizabeth Warren (D-Mass.), who attended the meeting with representatives from the departments of Defense, Energy, Health and Human Services, and the Federal Emergency Management Agency.

Sen. Richard Blumenthal (D-Conn.), who requested the meeting, added that based on initial estimates, “I am going to press for at least $10 billion to $15 billion.”

“There has to be an immediate triage plan but also a longer-term plan,” he added.

Senate Majority Whip John Cornyn (R-Tex.) said Monday that he expects the Senate will vote sometime in "the last half of October" on additional disaster aid. Lawmakers are waiting for the White House to send full details of how much federal relief agencies expect they will need to keep up with high demand.

“I think they will give us a time frame for when we need to act,” Cornyn said. “We’re actively pulling together our numbers and hope to have something to the appropriators later this week.”

FEMA is required by law to complete a full damage assessment before requests for reconstruction money can be made. By Sunday, the agency had registered nearly 3 million people seeking federal disaster assistance and was involved in ongoing disaster response in 20 states and the two island territories.

“The complexity of this job and the herculean effort of the people behind me and the federal government has been incredible,” FEMA Administrator William “Brock” Long told ABC’s “This Week” on Sunday.

Without a voting representative in the House and Senate, building political support for Puerto Rico and the U.S. Virgin Islands will require a bipartisan network of lawmakers with personal ties to the island or who represent districts with large voting blocs from the territories.

Rep. Nydia M. Velázquez (D-N.Y.), who represents parts of Brooklyn and Manhattan and was born in Puerto Rico, said that a robust aid package might encourage island residents to stay put and not strain resources in mainland states.

"We all know that Puerto Ricans are resilient and will do what it takes, that they're dedicated to rebuilding their island. But there has to be a federal partnership. Otherwise, Puerto Ricans are going to lose hope and leave the island," she said.

Kelsey Snell and Nick Miroff contributed to this report.