Helicopters scrambled Monday to contain a days-old blaze that felled a third tank at a fuel depot in Cuba, as the search continued for 16 missing firefighters.

According to an official update, the confirmed toll from the fire was one 60-year-old fireman dead, with 24 people hospitalized -- five of them in critical condition.

More than 100 others were injured, most suffering burn wounds, and some 5,000 people have been evacuated from around the disaster zone, authorities reported.

The fire on the outskirts of Matanzas, a city of 140,000 people 100 kilometers (60 miles) east of Havana, broke out late Friday after lightning struck one of eight tanks at the depot.

On Monday, the governor of the western Matanzas province said the blaze had spread to a third tank, which collapsed like two others before it did over the weekend.

"The third tank also collapsed, after the second spilled its fuel" as it caved in on Sunday, governor Mario Sabines told state TV.

He said the blaze area was "very big" and the containment effort "very complex."

Deputy fire chief Alexander Avalos Jorge said later Monday that as a result of that collapse, a fourth tank has also been affected.

"It's been a chain reaction," he said.

Aircraft, firefighters and other specialists and equipment arrived in Cuba from Mexico and Venezuela on Sunday after the island nation asked for help from "friendly countries."

Sabines said the teams were preparing an operation to douse the flames with foam, "but this could take a while."