WASHINGTON — Sen. Marco Rubio has a message for the Trump administration and his Republican colleagues: Puerto Rico has massive logistical challenges in recovering from Hurricane Maria that are at risk of getting worse, not better.

"If tomorrow we authorize $10 billion of aid to Puerto Rico, we would struggle to deliver it," the Florida Republican told reporters after a meeting at the White House on Tuesday.

"The emergency issue before us today is not money in the next 24 to 48 hours," Rubio said. "The emergency issue we have today is the capacity to deliver and distribute aid to the places that need it the most, and that today is still not in place."

Rubio said the USS Comfort relief vessel was on the way to Puerto Rico from Norfolk, Va., and he was pleased to see a new level of emphasis from the Trump administration Tuesday.

"I'm encouraged to see that increase in intensity today," Rubio said. "The logistical challenges are real. You can't drive restoration trucks onto the island. They have to be sent there by barge or flown in by airlift, so that in and of itself presents challenges."

Rubio also briefed his fellow Senate Republicans on the dire situation in the territory, which he visited Monday, traveling with the Coast Guard and seeing Resident Commissioner Jenniffer Gonzalez-Colon and Federal Emergency Management Agency Administrator Brock Long.

"Our conventional method of responding to a storm requires the federal government to kind of plug in to the existing emergency response of a state, and then work through them," he said.

It can take up to a week for barges to arrive from Florida ports.

"We have a barge leaving tomorrow," Rubio said. "It will not be there for five to six days."

While Rubio said he was sure Congress would supply needed funding, 10 Democratic senators, led by New Jersey's Robert Menendez and Cory Booker, wrote to Speaker Paul D. Ryan and Senate Majority Leader Mitch McConnell calling for immediate emergency supplemental aid to Puerto Rico and the U.S. Virgin Islands, including FEMA money and Community Development Block Grant funding for rebuilding.

"As members of Congress, we have an obligation to ensure all citizens of the United States affected by natural disasters have sufficient resources to recover. Congress can and should come together to help our fellow Americans recover just like it has in past disasters," the senators wrote. "Without this crucial funding, Puerto Rico and the U.S. Virgin Island's schools, businesses and critical infrastructure will be left vulnerable to further deterioration, only prolonging an already challenging road to recovery and adding to human suffering."

The group led by Menendez and Booker does not want to wait for the Office of Management and Budget to send over formal estimates on what is needed on the islands, which could push off action on a supplemental until mid-October.

The funding need might not be quite so dire, as the FEMA Disaster Relief Fund is replenished as of Oct. 1 under the continuing resolution that already has become law to the tune of $6.7 billion. But more disasters would necessitate more money.

Emergency appropriations likely would replenish the disaster relief fund across the board, though some departments and agencies might need additional funds for the response in the territories.

While Menendez has been absent from the Capitol during his ongoing corruption trial at the federal courthouse in Newark, he has been engaged in the recovery efforts in Puerto Rico.

In addition to Tuesday's letter, he is working on arranging a congressional delegation to visit the island as early as later this week, according to his office. Menendez also is working on a request that President Donald Trump invoke the Defense Production Act to get access to civilian aircraft, fuel and generators to help address the lack of electricity on the island.

That's as Trump has announced he intends to visit the island next Tuesday, which he said was the first day possible given the logistical issues facing responders there.

"Puerto Rico is very important to me," Trump said. "I grew up in New York, so I know many people from Puerto Rico. I know many Puerto Ricans. And these are great people, and we have to help them. The island is devastated."

Another New Yorker, Senate Minority Leader Charles E. Schumer, said after speaking with the governor of Puerto Rico, he believed the federal government needed to provide at least 1,000 people just for basic security.

He also called for Puerto Rico to be shipped "at least 200 generators, right now" due to lack of electricity.

Rubio also said he wants to make sure the full breadth of the federal government's resources are deployed on the island, noting roads remain impassable and the construction resources of the Army Corps of Engineers will be needed, among other capabilities.