SAN JUAN, Puerto Rico — President Trump blasted the increasingly critical mayor of this capital city 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 San Juan Mayor Carmen Yulin Cruz 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."

He said the mayor and "others" on the island "want everything done for them."

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 the reports were not fair to responders or their efforts.

Five hours later, a second set of tweets from Trump set a somewhat-softer tone: "To the people of Puerto Rico: Do not believe the #FakeNews! #PRStrong," the president tweeted. "We must all be united in offering assistance to everyone suffering in Puerto Rico and elsewhere in the wake of this terrible disaster."

Cruz, in emotional appeals on TV on Friday, has become the face of Puerto Rican officials distraught over what some charge is an insufficient response by the U.S. government to the crisis from Hurricane Maria, which killed at least 16 people on the island.

While Trump described the federal response as "amazing," Cruz publicly called on the president 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."

Cruz, in a Saturday appearance on MSNBC's AM Joy, said it wasn't just her saying the island needs help. Army Lt. Gen. Jeffrey Buchanan, the Washington Post reported, said Friday there was a lack of people and assets to assist the island.

"(A) three-star general (is) saying we don't have enough," she said. "So, it's not only me."

Cruz said she wouldn't be "distracted by small comments, by politics, by petty issues. This is one goal and it is to save lives. That's all that matters. Whomever says things that can help will be praised, whomever doesn't will not."

Cruz said she'd be willing to meet with Trump when he visits Puerto Rico on Tuesday.

"If Mr. Trump wants to see me, I would be very glad to meet with him," she said. "He's the president of the United States. I afford him the same respect that I afford the leader of every other nation of the world that was democratically elected."

While increasing amounts of water, food and medicine have 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 the 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."

Trump also noted that he and the first lady will be traveling to Puerto Rico and possibly the U.S. Virgin Islands, which were also battered by Hurricanes Irma and Maria. Trump noted in the Virgin Islands, another U.S. territory, "people (are) working hard."

Five hours later, he came back with a slightly softer tone in another series of tweets: "Despite the Fake News Media in conjunction with the Dems, an amazing job is being done in Puerto Rico. Great people!"

Trump followed that up with tweets praising Puerto Rico Gov. Ricardo Rosselló and Congresswoman Jennifer Gonzalez-Colon.

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.”

Rosselló said Saturday that he only heard about Trump’s morning tweets when a reporter read them to him, but that he has spoken multiple times to the president, as well as Vice President Mike Pence in recent days.

“He has reiterated his commitment and that we are a priority,” Rosselló said at a news conference. “And he has shown that whenever we have asked he has delivered.”

He began his remarks by stressing the importance of cooperation between local and federal authorities.

“We want to stress the unity of purpose that federal government, DOD (Department of Defense), local government and municipalities are trying to establish to bring this recovery to Puerto Rico,” Rosselló said.

“The only way for this to work is to stress collaboration. I am committed to collaborating with everyone,” he said. “This is a moment where we have to serve the people of Puerto Rico.”

The death count to date is 16, but “based on the devastation it will likely go up,” Rosselló said.

In an update on relief efforts, Rosselló said the number of open gasoline stations 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 telecommunications 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.

Stanglin reported from McLean, Va.