[Read more about what the prime minister of the Bahamas called a “historic tragedy.”]

He said Marsh Harbour’s area was underwater and “looks like a lake.” He noted that Treasure Cay’s airport is O.K., but that the roads are flooded. He also said the Haitian shantytown known as the Mudd was “completely destroyed or decimated.”

Mr. Minnis said the government is sending police and defense force officers to the island to address safety and security concerns. He said the government hopes to prevent the security issues, such as violence and looting, often seen in other countries following disasters.

The Coast Guard is trying to help in the Bahamas.

The United States Coast Guard has sent seven helicopters to the Bahamas to help with rescue efforts, but the continued severe weather was making it difficult for them to reach the hardest-hit islands, Rear Adm. Todd Sokalzuk said on Tuesday.

Admiral Sokalzuk, the deputy commander of the Coast Guard’s Atlantic Area, said that about 35 people had been evacuated by helicopter from Marsh Harbour, the main town in the Abaco Islands. Some had been injured by the storm; others were patients hospitalized at a local clinic that was damaged.

Low visibility and high turbulence have thwarted helicopters from getting to Grand Bahama Island despite two days of trying, the admiral said. “At this point we have only been getting somewhat west of the Abacos,” the admiral said. “We are very anxious for the weather to clear to get into Grand Bahama Island.”

The admiral said airports on both Grand Bahama and Great Abaco were still awash with seawater, and roads had been washed out. “Based on the devastation we have seen in the Abacos, we think it will probably be worse in Grand Bahama,” he added. “Because the storm sat there for so long, there is probably increased damage. There are potentially more people that need assistance.”

The United States Customs and Border Protection also sent a helicopter and, at the request of the Bahamian government, is helping to ferry Royal Bahamian Police Force officers to the affected islands and then evacuate injured people on the return trip, the admiral said.