WASHINGTON (REUTERS) - US President Donald Trump said on Monday (Sept 25) that Puerto Rico is in "deep trouble" after being hit by Hurricane Maria and that its billions of dollars of debt to the Wall Street and banks "must be dealt with."

"Puerto Rico, which was already suffering from broken infrastructure & massive debt, is in deep trouble," Trump wrote in a series of posts on Twitter. "It's (sic) old electrical grid, which was in terrible shape, was devastated. Much of the Island was destroyed, with billions of dollars owed to Wall Street and the banks which, sadly, must be dealt with."

Trump did not offer a pathway for dealing with Puerto Rico's debt. The US territory, struggling with US$72 billion (S$97 million) in debt, filed the biggest government bankruptcy in US history earlier this year.

Maria, the most powerful hurricane to hit Puerto Rico in nearly a century, devastated the Caribbean island when it struck the US territory with ferocious winds and torrential rains last week.

Puerto Rico Governor Ricardo Rossello on Monday asked for more government aid to avert a humanitarian crisis in the island, which is home to 3.4 million people.

Puerto Rico's government on Monday asked a judge for up to four extra weeks to meet key deadlines in its bankruptcy case after Hurricane Maria brought its fragile infrastructure to its knees.

White House spokesman Sarah Sanders told reporters in Washington that the administration was engaged in a fact-finding process to figure out how much help Puerto Rico needs.