ROME (AP) — Six Russians were killed and two others were seriously injured when their snowmobile, pulling a sled, veered off an Italian Alpine ski slope during a nighttime drive, slammed into a fence and was hurtled through the air for hundreds of meters.

When rescuers arrived Friday night, the six victims were already dead on the slope of Mount Cermis, in the Trentino-Alto Adige region of northeast Italy, said Cavalese Fire Department Cmdr. Roberto Marchi.

"It is clear that the fundamental cause is recklessness and imprudence," Marchi told Sky TG24 TV in an interview on the slope Saturday.

The slope is labeled "pista nera" or black ski run, indicating a level of steepness and other difficult conditions suitable only for the most experienced skiers.

Cavalese Mayor Silvano Welponer said that putting eight persons in the vehicle — a driver and passenger in the snowmobile and six passengers in the sled behind — "made for a very heavy load. You have to know what you are doing and have the experience" to safely handle that, he said.

The ANSA news agency said authorities were performing tests to determine if the snowmobile's driver — who survived the fall — was drunk.

The sled-towing snowmobile cut a spectacular trajectory after it veered off the slope on a curve, hit the barrier on the slope's edge and was sent hurtling through the air, Italian news reports said. The vehicle sheared off the tips of tree branches as it flew through the air, and its occupants landed dozens of meters away.

RAI state radio reported that the slope was unlit.

The Russian consul general in Milan, Alexei Parmonov, said on Russian state television that he was in contact with Italian investigators, who he said suspect the crash was caused by excessive speed. They also were checking the possibility of a mechanical malfunction.

Following procedure for cases of fatal accidents, Italian prosecutors formally opened a probe to see if manslaughter charges should be filed, Italian news reports said.

Parmonov identified the four men and two women who died in the crash. Five of them and also one of the injured men were tourists from Krasnodar, a region in southern Russia that includes Sochi, which is preparing to hold the 2014 Winter Olympics.

One of the dead women and the other injured man worked in Italy in the tourist industry.

The Russian diplomat gave the names of the dead: Denis Kravchenko, Irina Kravchenko, Vyacheslav Sleptsov, Yulia Yudina, Lyudmila Yudina and Rafilya Pshenichnaya. The injured, he said, were Boris Yudin and Azat Agafarov. All except Pshenichnaya and Agafarov were tourists from Krasnodar.

Yudin's 17-year-old son, who stayed behind in the hotel, lost his mother and sister in the accident, while his father was hospitalized with multiple fractures, Parmonov said.

Mount Cermis has a tragic history.

In 1998, a U.S. Marine jet, flying low on a training run from a nearby air base, accidently sliced a ski gondola's cable, sending the cable car crashing to the ground and claiming 20 lives. The accident triggered months of tensions between Italy and the United States, two traditional good allies.

In 1976, a ski gondola broke off from its cable and plunged to the slope, killing 42 persons.

A day of entertainment had been planned for the Val di Fiemme ski resort area, ahead of World Cup cross-country ski competition, but the festivities were canceled because of the snowmobile accident.

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