The Trump administration had said earlier this week that there was no need to waive the Jones Act to Puerto Rico, because it would do nothing to address the island's main impediment to shipping, damaged ports.
His ominous tweet drew immediate criticism from Democratic politicians who said Trump is applying a different standard to the island than he did to Texas and Florida when they were recently struck by hurricanes.
Trump wrote on Twitter: "The fact is that Puerto Rico has been destroyed by two hurricanes".
He also raised again the issue of Puerto Rico's $72 billion debt, which has forced the island's government to accept a federally appointed oversight board that effectively controls fiscal policy.
Hours-long lines have been the norm at island gas stations as people scramble to find fuel for generators and cars.
"The lack of planning and preparation is literally costing lives", said Mark-Viverito, who was born in San Juan.
Top 10 most infamous natural disaster in the last 100 years.
"The President and I will not be fully satisfied, however, until every Puerto Rican is back home, the power is back on, clean water is fully available, schools and hospitals are fully open, and the Puerto Rican economy is working", said Duke. And we're bringing them onto the island as we speak.
Aid was being distributed by the Federal Emergency Management Agency.
View Slideshow Some parts of the island still haven't received necessary supplies since Hurricane Maria struck. Dallas Mavericks
"Oversight now also could help prevent a worsening of the human tragedy that is unfolding and could help ensure that the lessons our Committee identified from past federal responses are implemented by the Trump Administration".
Asked about the reaction to her remark, Duke says: "There is so much more to do".
"Basically the whole day goes by doing these simple errands", he says. About 200 people exited Puerto Rico on a special Delta humanitarian flight, he said.
Joint Chiefs Chairman Gen. Joseph Dunford followed the same rhetoric, saying the military would "do everything [it] can to help them out" but that the help would be dependent on securing and rebuilding Puerto Rico's airfields and ports.
Accused of showing indifference to its plight as he feuded with NFL football players, he has since pledged a massive relief effort and will visit the hurricane-battered island on Tuesday.
Trump's not the only one talking up the administration's response.
There should be more help and less spin coming from Washington.
"I know it's a hard storm to recover from but the amount of progress that's been made - and I really would appreciate any support that we get".