President Trump blasted the increasingly critical mayor of San Juan, Puerto Rico, Saturday for "poor leadership ability" in not being able to "get their workers to help" in hurricane relief, saying the federal government is doing a "fantastic job."

The president said Carmen Yulin Cruz, the mayor of the island's capital, had been complimentary to him only a few days ago, but "has now been told by the Democrats that you must be nasty to Trump."

In a series of tweets, he also slammed "Fake News CNN and NBC," which he said "are going out of their way to disparage our great First Responders as a way to 'get Trump.'" He said their reports were not fair to the responders or their efforts.

At least 16 people were killed by Hurricane Maria when the storm hit last weekend.

Cruz, in emotional appeals on TV on Friday, has become the face of Puerto Rican officials distraught over what some of them charge is insufficient response by the U.S. government to the crisis.

While Trump has called the federal response "amazing," the mayor has appealed publicly to Trump by name to speed up the delivery of food, water, medicine and fuel, and "to make sure somebody is in charge that is up to the task of saving lives.”

"I will do what I never thought I was going to do. I am begging, begging anyone who can hear us to save us from dying," Cruz said Friday. "If anybody out there is listening to us, we are dying, and you are killing us with the inefficiency."

While increasing amounts of water, food and medicine has been arriving on the island of 3.4 million people as a distribution bottleneck eases, many — particularly in remote and mountainous areas — remain desperate for water and other necessities.

In the face of pointed criticism from the mayor and other Puerto Rican officials, Trump unleashed a series of tweets Saturday morning, saying "...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."

He also noted that he and the first lady will be traveling to Puerto Rico and possibly the U.S. Virgin Islands, which were also hit by hurricanes. Of the latter, he noted in that U.S. territory "people working hard."

Cruz, who has appeared regularly on U.S. cable news programs, was particularly pointed in rejecting a statement by acting Homeland Security secretary, Elaine Duke, who called the government’s response "a good news story in terms of our ability to reach people and the limited number of deaths that have taken place.”

The mayor retorted: "This is, damn it, this is not a good news story. This is a ‘people are dying’ story. This is a ‘life or death’ story. This is ‘there’s a truckload of stuff that cannot be taken to people’ story. This is a story of a devastation that continues to worsen.”

On Saturday morning, Puerto Rico Gov. Ricardo Rosselló provided an update on relief efforts, saying the number of gasoline stations now open has increased from 450 four days ago to 714. He said 11 regional staging areas have been receiving food and water across the island and that telecommunication has been restored in several key municipalities, including San Juan.

He also said the stockpiles of fuel have increased to 600,000 barrels of diesel and 722,000 barrels of gasoline.

Contributing: Oren Dorell in San Juan, Puerto Rico