U.S. President Donald Trump said Tuesday he'll visit hurricane-ravaged Puerto Rico.

Trump announced the visit after his administration was criticized for its response to the damage on the island that is home to more than three million U.S. citizens. The island has been coping with shortages of food, drinking water, electricity and various forms of communication after Hurricane Maria struck earlier this month.

Trump said next week is the earliest he can visit Puerto Rico without disrupting recovery operations.

"We have shipped massive amounts of food and water and supplies to PR and we are continuing to do it on an hourly basis," he said.

Trump also agreed to boost federal disaster aid to the island, increasing funding to assist with debris removal and emergency protective measures, the White House said in a statement.

Trump tweets

Donald Trump tweeted about Tuesday's Republican primary in Alabama as much as U.S. territory Puerto Rico in recent days, with tweets about the protests during the national anthem dwarfing all other subjects. (CBC)

While appearing at a joint news conference with Spanish Prime Minister Mariano Rojoy later Tuesday, Trump said he would also visit the U.S. Virgin Islands, which also felt Maria's impact.

"We're doing everything in our power to help the hard-hit people" of both Puerto Rico and the U.S. Virgin Islands, he said.

Not 'preoccupied with NFL'

The president has drawn criticism for focusing less on the storm's impact in recent days and more on NFL players and their silent protests against the treatment of minorities, beginning with a speech in Alabama on Friday and then a series of tweets. 

"I wasn't preoccupied with the NFL, I was ashamed of what was taking place," said Trump when asked at Tuesday's news conference. "To me, that was a very important moment. I don't think you can disrespect our country, our flag, our national anthem."

Puerto Rico Hurricane Maria

Lines of cars and people with gas cans try to get fuel from a service station in the aftermath of Hurricane Maria, in Aibonito, Puerto Rico, on Sept. 25. (Gerald Herbert/Associated Press)

Trump didn't specify what "moment" he was referring to and why the issue has suddenly become a White House priority. Colin Kaepernick first staged a protest during the national anthem at a game in August 2016, and similar protests in the NFL were relatively muted during the first two weeks of this regular season. By contrast, some 200 players participated the past weekend after Trump's intervention.

Trump's war of words with athletes, which also included NBA players, led to a series of angry responses on social media, including from singer and Puerto Rico native Marc Anthony. Trump also drew criticism for a tweet Monday night related to Maria's impact on the island which brought up Puerto Rico's longtime difficulties with restructuring its "massive debt."

Relief operations arriving by air

Puerto Rico Gov. Ricardo Rossello said he spoke to Trump about the crisis Hurricane Maria caused on the island. He said he's "confident the president understands the magnitude of the situation."

Speaking to reporters Tuesday at a Puma gas facility in San Juan, Rossello said Trump "has offered a waiver on matching funds" for aid from FEMA, which means the cash-strapped island won't have to contribute to the initial costs of this federal help.

Late Tuesday, amid a growing chorus of criticism, the Trump administration said it was sending a flotilla of ships and thousands more military personnel to Puerto Rico to address the humanitarian crisis.

"We're dramatically increasing the federal footprint that's there," FEMA administrator Brock Long said, speaking outside the White House.

Puerto Rico Hurricane Maria

This combination of photos released by National Oceanic and Atmospheric Administration shows Puerto Rico at night on July 24, top, before Hurricane Maria, and on Sept. 25, days after the hurricane wiped out most of the island's power. (NOAA via Associated Press)

The Pentagon said the number of active duty military personnel would grow from about 2,500 to possibly double that number in the next several days. 

An army brigadier-general will take over command of the military response, which will include additional medical facilities and satellite communications equipment, said John Cornelio, spokesperson at U.S. Northern Command. USNS Comfort is expected to leave Baltimore by Saturday and arrive in Puerto Rico three to five days later. 

The military response will also include a civil affairs unit from Fort Bragg, N.C., that will be used to help communicate with the residents on the island, Cornelio said. The unit will use loudspeakers, trucks, leaflets and text messaging to get needed information to the public. 

Puerto Rico Hurricane Maria

Jose Garcia Vicente, right, works with Jose Colon, as he starts to salvage his destroyed home, in the aftermath of Hurricane Maria, in Aibonito, Puerto Rico, on Monday. (Gerald Herbert/Associated Press)

Additional National Guard forces are being sent to provide more security on the island. Those forces will be under the command of the governor, and could be used around fuel access points where there have been some security problems. 

Long said the federal government has provided four million ready-to-eat meals and six million litres of water. That would account for less than a day's supply for each of the island's 3.4 million U.S. citizens. 

Large sections of the territory remained without adequate food, water and fuel Tuesday. Flights off the island were infrequent, communications were spotty and roads were clogged with debris. Officials said electrical power may not be fully restored for more than a month.

With files from CBC News