President Trump took a shot at Puerto Rico and Carmen Yulín Cruz, the mayor of San Juan and a frequent critic of the president, as the island braces for Tropical Storm Dorian. Mr. Trump wrote on Twitter that the storm was headed "as usual" to Puerto Rico, and urged residents to be grateful to the Federal Emergency Management Agency (FEMA).

"We are tracking closely tropical storm Dorian as it heads, as usual, to Puerto Rico. FEMA and all others are ready, and will do a great job. When they do, let them know it, and give them a big Thank You - Not like last time. That includes from the incompetent Mayor of San Juan!" Mr. Trump said, referring to Hurricane Maria, which devastated the island.

In another tweet, Mr. Trump castigated Puerto Rico as "one of the most corrupt places on earth." He also said that he was "the best thing that's ever happened to Puerto Rico!"

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Forecasters have warned that heavy rain could cause landslides, heavy flooding and power outages in the U.S. territory still recovering from Maria almost two years later.

Mr. Trump ordered a state of emergency in the territory on Tuesday evening, which will allow federal assistance to help local response efforts stemming from Tropical Storm Dorian.

He also repeated an incorrect statistic in a tweet on Tuesday, saying that the territory had received $92 billion in aid in the wake of Maria. Congress has allocated $42.5 billion to Puerto Rico, but the island had received only $14 billion as of May.

"Wow! Yet another big storm heading to Puerto Rico. Will it ever end? Congress approved 92 Billion Dollars for Puerto Rico last year, an all time record of its kind for "anywhere.'" Mr. Trump wrote, incorrectly.

Tropical Storm Dorian is approaching the island after several weeks of political upheaval, culminating in the resignation of former Gov. Ricardo Rosselló. Justice Secretary Wanda Vázquez was sworn in as Puerto Rico's latest governor earlier this month, hours after the island's Supreme Court overturned the swearing in of Pedro Pierluisi as governor.