An avalanche struck a group of 33 climbers on Mount Mizhirgi in Russia's North Caucasus republic of Kabardino-Balkaria at about 5 p.m. on Sunday, September 6, killing 11 people and leaving six unaccounted for, the regional branch of the Emergency Situations Ministry (MChS) said.

Ten climbers descended on their own, while six others were injured and taken to hospitals, the ministry said. A search-and-rescue operation involving 56 people is underway.

The work is hampered by difficult terrain and a continuing avalanche risk. If weather improves, authorities plan to deploy an MChS Mi-8 helicopter and a commercial helicopter to the search.

An adverse weather warning had been in effect for the area at the time of the incident, the ministry said. The Investigative Committee has opened a criminal case on charges of negligence.

The ministry initially reported that a group of 15 climbers had been caught in the avalanche, with two dead, three injured and ten unaccounted for, before revising the figures.