The mayor of Puerto Rico's biggest city has berated a Trump cabinet official who called the US response to Puerto Rico, "a good news story". Photo: Getty Images

Homeland Secretary Elaine Duke had said she was "very satisfied" with progress, calling it "a good news story in terms of our ability to reach people".

The San Juan mayor hit back: "Damn it, this is not a good news story. This is a people are dying story."

Over a week after Hurricane Maria struck, millions still need urgent aid.

The category 5 hurricane, the most powerful to hit Puerto Rico in at least 90 years, has claimed 16 lives on the island and left millions lacking medicine, food, cellular communications, shelter, and clean water.

"Well maybe from where she's standing it's a good news story," Mayor Carmen Yulin Cruz told CNN as Mrs Duke was preparing to board a plane for Puerto Rico, a US island territory.

"When you're drinking from a creek, it's not a good news story. When you don't have food for a baby, it's not a good news story."

Around 44% of Puerto Ricans lack access to potable drinking water, and utility officials say it may takes months before electricity is restored, allowing clean water to begin flowing again.

After arriving on the storm-ravaged island, Mrs Duke told reporters: "Clearly the situation here in Puerto Rico after the devastating hurricane is not satisfactory."

"But together we are getting there and the progress today is very, very strong," she added.

Shipping containers stocked with emergency supplies are piling up in San Juan, the capital city, and US and local officials are attempting to rally lorry drivers to help deliver the supplies to remote corners of the island.

"Everything has been wiped out... we're literally starting from scratch," President Donald Trump said in Washington on Friday morning.

On Thursday, he lifted shipping restrictions to help fuel and supplies reach the storm-ravaged island.