ROME, Aug. 21 (Xinhua) -- Italian authorities have no idea yet how many people are missing in a flash flood that occurred Monday in southern Italy, which has killed at least 10 people, an official said Tuesday.

At least 10 hikers, six women and four men, died in a flash flood that occurred Monday in southern Italy, Cosenza Prefecture spokeswoman Antonella Vecchio confirmed to Xinhua.

The flood engulfed the hikers along the banks of the Raganello River, which creates a scenic gorge that is 12 km long and 400 meters deep in the Pollino National Park in the southern Calabria region.

Initial reports that 11 people were dead were later revised by the Civil Protection Agency on the night.

A total of 33 people have been rescued and 11 have been hospitalized, including a little girl who was found in a state of hypothermia and has since been transferred to a hospital in Rome, Vecchio said.

She would not disclose the extent of the child's injuries.

A Dutch citizen was among those hospitalized, Vecchio said.

Vecchio said that the search and rescue effort is ongoing but the authorities have no idea how many people are missing because the gorge is accessible to organized groups with guides as well as hikers who decide to go on their own.

There was one organized group of 18 people, Vecchio added.

As many as 36 men, women and children, plus a guide, were reportedly involved in the flood that occurred due to heavy rains.

Speaking to Sky TG24 private broadcaster, Calabria Civil Protection Agency Chief Carlo Tansi said the flood occurred in a very narrow part of the gorge that runs between very high rock faces.

"We recovered some of the bodies three kilometers downstream from where the flood rose," he said, adding that the area has been getting rainstorms on a daily basis for the entire month of August.

The rescue effort, which continued overnight, has mobilized firefighters, alpine rescue units, divers, a helicopter and rescuers who specialize in exploring caves and mountainous areas.