Donald Trump has told Puerto Ricans that its recovery after Hurricane Maria has put his "budget a little out of whack".
President Donald Trump is visiting Puerto Rico to reassure the island struggling to recover from a devastating hurricane.
One of the first people Trump met when he and his wife, Melania, touched down in San Juan on Tuesday was the city's mayor, Carmen Yulin Cruz, who has repeatedly blasted Trump as showing insufficient concern about the US territory's plight.
Trump, who has grappled with hurricanes Harvey, Irma and Maria in the past six weeks, praised the federal assistance so far in Puerto Rico but also mentioned cost.
"I hate to tell you, Puerto Rico, but you've thrown our budget a little out of whack because we've spent a lot of money on Puerto Rico," he said. "And that's fine, we've saved a lot of lives."
A few days earlier Trump had lashed out at Cruz on Twitter for "poor leadership". He cited "politically motivated ingrates" and said some people on the island "want everything to be done for them".
Trump shook hands with Cruz after his arrival but he saved his warm words of praise for other local and federal authorities.
"You are a bad hombre," said a sign held by a woman along the route.
Trump and his wife, Melania, met survivors of the disaster in the nearby town Guaynabo, walking down a street and talking to several families whose homes were damaged. The sidewalks were piled with debris.
Trump had criticism of his own about the local response.
"Their drivers have to start driving trucks," he said at the White House. "So on a local level, they have to give us more help. But I will tell you, the first responders, the military, FEMA, they have done an incredible job in Puerto Rico."
The economy of the US territory, home to 3.4 million people, already was in recession and its government filed for bankruptcy in May. The storm wiped out the island's power grid, and less than half of residents have running water.
Two weeks after Maria, it is still difficult for residents to get a cell phone signal or find fuel for their generators or cars.
Trump got high marks for his handling of Hurricane Harvey in Texas and Hurricane Irma in Florida and the Caribbean.
Caught off guard by the severity of Hurricane Maria's damage to Puerto Rico, Trump did not focus on the storm for days.
Trump's administration has transferred more than $US20.5 million ($A26.2 million) in federal funds to Puerto Rico to defray disaster expenses, FEMA said on its website.
The administration is preparing to ask Congress for $US13 billion in aid for Puerto Rico and other areas hit by natural disasters, according to congressional sources said.
But that money will only go so far. The island's recovery will likely cost more than $US30 billion.