An earthen dam from a mountain fluoride mine in the northern Italian Alps burst today, sending tons of mud and rock down on homes and hotels in a mountain valley. By tonight, 68 bodies had been recovered and about 200 more were unaccounted for and feared dead.

The 3-mile mud flood rushed down the Fiemme Valley into the town of Stava, in the Trentino area of the Dolomite Mountain region, at lunchtime, wiping out three small tourist hotels and dozens of vacation homes. Rescue officials said most of the victims appeared to be Italians.

At a news conference in Stava, Minister of Civil Defense Giuseppe Zamberletti said that he expected the death toll to mount as 4,000 rescue workers, backed by bulldozers, worked through the night to dig through the mud deposits for additional victims. Rescue officials estimated that there were 200 to 300 people in the area when the dam burst.

"It was as if it was the end of the world," said the mayor of the village of Tesero, outside Stava, as he recalled the wall of water and mud rushing down the valley. "It was horrible."

"It sounded like an earthquake," one survivor said. "I thought the mountain had collapsed."

At about 12:55 p.m. local time, a small earthen dam that collected runoff water from a fluoride mine burst when a dirt restraining wall apparently gave way under the pressure of excessive runoff from days of heavy alpine rains upstream. The collapse sent a brown tongue of mud and rock rushing down the valley, whose stream banks were dotted with holiday bungalows and at least four small, wooden hotels.

In 20 seconds, three of the hotels -- the Erika, the Stava and the Miramonte -- were crushed as the hotel guests, mostly Italian tourists, were sitting down to lunch. Only piles of broken timbers were left in the mud after the flood passed. A fourth hotel, the Dolomiti, was severely damaged.

It was Italy's worst dam disaster since 1963, when a landslide killed more than 2,000 people after a dam collapsed at Longarone, 35 miles east of Stava.

The dam that burst today was part of a dirt-enclosed mountain reservoir for waste water from a small fluoride mine run by a company called Prealpi Mineraria, once a subsidiary of Italy's large Montedison chemical company.

According to initial investigations, a dirt restraining wall of the small reservoir gave way under the pressure of large rain runoffs, sending the wall of water, mud and rock down on the valley villages below.