Libya's devastating flood has transformed Derna from a busy port welcoming fishing boats and ships loaded with goods and passengers into a dump brimming with rubble, car wrecks and dead bodies.

Tugboat captain Ali al-Mismari, 60, recalled the night of September 10 when torrential rains caused by Storm Daniel battered the eastern Libyan city, bursting two dams and wiping out entire neighborhoods.

At first, Mismari told AFP, he wanted to take his boat, the "Irasa", out of the harbor to avoid putting the crew at risk and to avoid damage to the vessel.

But in the chaos of the storm, with water levels rapidly rising, he was unable to see the seawalls surrounding the port and navigate a safe exit.

"There was nothing (to do) but pray," he said.

When day broke, the scale of the devastation became clear.

Mismari said he saw "massive trucks, car tires, people, houses, entire palm trees... heaters, washing machines, refrigerators" had all been washed into the harbor by the flash flood.

The official death toll from the disaster stands at more than 3,300 -- but the eventual count is expected to be far higher, with international aid groups giving estimates of up to 10,000 people missing.