DONALD TRUMP launched a Twitter tirade against the mayor of storm-ravaged Puerto Rican capital San Juan after she begged the US President for help following a slow American response to hurricane Maria.

Carmen Yulin Cruz accused the Trump administration of “killing us with the inefficiency” and implored the president, who is set to visit the US territory on Tuesday, to “make sure somebody is in charge that is up to the task of saving lives”.

Trump attacked the mayor in response, insisting: “They want everything to be done for them when it should be a community effort…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.”

Tweeting from his golf club in New Jersey, Trump tried to discredit Cruz with an unsubstantiated accusation. “The Mayor of San Juan, who was very complimentary only a few days ago, has now been told by the Democrats that you must be nasty to Trump,” the president said.

He added that military personnel and emergency services had done “an amazing job” despite having “no electric, roads, phones etc”.

Trump's acting homeland security secretary, Elaine Duke, surveyed the Puerto Rican landscape by helicopter during a visit on Friday. She also drove past still-flooded streets, twisted billboards and roofs with gaping holes, and offered encouragement to some of the emergency personnel the US Government has on the ground.

Duke also tried to move on from the remarks she made on Thursday in which she called the federal relief effort a “good-news story”.

Cruz said: “We are dying, and you are killing us with the inefficiency. I am begging, begging anyone that can hear us, to save us from dying.”

Many people remain desperate for necessities, most urgently water, long after the September 20 hurricane. Telecommunications have yet to be restored to 70 per cent of the island and only half of the supermarkets have reopened.