US President Donald Trump has blasted the mayor of San Juan, Puerto Rico, for her “poor leadership” after Mayor Carmen Yulín Cruz begged for help in handling the crisis and devastation caused by Hurricane Maria.

In a series of early-morning tweets on Saturday, Trump blasted “...Such poor leadership ability by the Mayor of San Juan, and others in Puerto Rico, who are not able to get their workers to help”.

“They want everything to be done for them when it should be a community effort. 10,000 Federal workers now on Island doing a fantastic job.”

Acting Homeland Security Secretary Elaine Duke traveled to the island on Friday to help coordinate the government’s rescue and relief efforts, but faced lambaste by Cruz after she had described the situation in Puerto Rico as a “good news story.”

“Dammit, this is not a good news story,” Cruz responded with shock and anger. “This is a people-are-dying story.”

"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. When you have to pull people down from buildings -- I�m sorry, that really upsets me and frustrates me," Cruz lamented.

The Trump administration placed Lt. Gen. Jeffrey Buchanan in charge of the military relief operations Thursday, but he said Friday that the Defense Department had not sent enough troops and vehicles to the island.

Trump insisted Friday that his administration was doing an “incredible job” with relief efforts.

"We have done an incredible job, considering there�s absolutely nothing to work with," Trump told reporters at the White House.