A tropical storm warning was issued on Friday for the northern Bahamas as UN Secretary General Antonio Guterres warned of the dangers of climate change during a visit to the hurricane-battered archipelago.

The Miami-based National Hurricane Center said a depression had formed near the Bahamas and was forecast to become a tropical storm today.

Bahamian meteorologists said the islands of Grand Bahama and Abaco, which were the worst-hit by Hurricane Dorian, were in the path of the approaching weather system.

Winds of up to 60 miles (100 kilometers) per hour were expected and heavy rainfall could bring some flooding to the already saturated islands, said Trevor Basden, director of the Department of Meteorology.

Carl Smith, a spokesman for the Bahamian National Emergency Management Agency (NEMA), said the storm could have an impact on relief and recovery efforts on Grand Bahama and Abaco.

"The weather system will slow down logistics," Smith told a press conference in Nassau, the capital of the Bahamas. "Fuel and water remain the biggest needs in Abaco."

UN chief Guterres said in a tweet that he had come to the Bahamas "to express my solidarity with the Bahamian people" and "ways we can continue supporting them."

In prepared remarks, Guterres said 75 percent of all buildings had been destroyed in some areas by Dorian, a Category 5 storm.

"Hospitals are either in ruins, or overwhelmed," he said. "Schools have been turned into rubble. Thousands of people will continue to need help with food, water and shelter."

Guterres said the hurricane demonstrated the need to address climate change.

"In our new era of climate crisis, hurricanes and storms are turbo-charged," he said. "They happen with greater intensity and frequency -- a direct result of warmer oceans.

"Science is telling us: this is just the start. Without urgent action, climate disruption is only going to get worse. Every week brings news of climate-related devastation."

NEMA raised the death toll, meanwhile, from Hurricane Dorian to 52 from 50 although officials have said they expect it to rise significantly once all the bodies are recovered.

A former prime minister, Hubert Ingraham, said this week he feared the final death toll could be in the hundreds.

Smith, the NEMA spokesman, said some 1,300 people remain unaccounted for following Hurricane Dorian -- the same number he gave on Thursday.

He said 71 people were staying in shelters on Grand Bahama island and 2,037 in shelters in New Providence, where Nassau is located.