Until now, Puerto Rico was bound by the Jones Act, which says that the island can only receive items from mainland America that is shipped via vessels built, owned and manned by Americans.
But not everyone is impressed by the administration's response as nearly half of Puerto Rico's residents remain without access to drinking water and almost the entire island lacks power amid a massive breakdown in infrastructure predicted to last months.
This is after accusing the San Juan mayor of poor leadership and being unable to get workers to help the US territory recover.
Donald Trump has said officials in hurricane-hit Puerto Rico "want everything to be done for them" in an astonishing attack on Twitter. "10,000 Federal workers now on Island doing a fantastic job (sic)", Trump added in a series of tweets.
That drew a sharp rebuke from San Juan Mayor Carmen Yulin Cruz, who told CNN, "This is a people-are-dying story". They need help. We can't let them die.
Trump's latest missive could further inflame sentiment after he had earlier weighed in on the emerging fight over how to finance the already debt-stricken territory's recovery - comments that were viewed as premature and distasteful by some.
His tweets came on the same day that some senior administration officials offered a vigorous defense of the federal response in Puerto Rico at a pair of White House briefings, even as they acknowledged the long road ahead.
US Vice President Mike Pence also defended his boss's performance by taking to Twitter. "There's no way for us to know if our family members are still alive or not, or what their condition is", said Omar Medina. They need thousands more. He said she had "poor leadership ability".
Trump fired back at Cruz in a tweet, accusing her of "poor leadership" and saying some Puerto Ricans "want everything to be done for them when it should be a community effort".
"If he asks to meet with me, of course I will meet with him", she said. But, he said, his administration's first responders are "amazing".
Mr Trump is expected to survey the damage on the island on Tuesday.
"Maybe from where she's standing it's a good news story".
"The people who are the best in this are the US military".
"Results of recovery efforts will speak much louder than complaints by San Juan Mayor".
Blumenthal adds the temporary suspension of the Jones Act, which requires goods shipped between points in the United States to be carried by USA built and operated boats, does not go far enough.
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