The twelve-person group, including two guides, embarked on the ascent of the 4,754-meter (15,597-foot) volcano on Tuesday, but ran into difficulty on Saturday when some members of the group fell nearly 4 200 meters, according to the authorities.
A person is believed to have a broken leg, authorities said.
Rescuers tried to reach them on Sunday but had to turn back because strong winds prevented their helicopter from landing.
“They were due to land at an altitude of 3,300 meters, but due to high winds of 30 meters per second (67 miles per hour), they were unable to do so, although two attempts were made within hours of each other” , said the rescuers.
Temperatures on the mountain can reach minus 14 degrees Celsius (7 Fahrenheit) overnight.
Tatyana Yukhmanova, a representative of the local civil defense authority, said rescuers will try to reach the group again tomorrow weather permitting.
Klyuchevskaya Sopka is the highest of the 160 volcanoes whose snow-capped peaks dominate Russia’s Kamchatka Peninsula.
It is part of a UNESCO World Heritage Site listed for its outstanding natural beauty.
Rescuers warn that the mountain, made up of mounds of volcanic rock mixed with snow and ice, is considered particularly dangerous for climbers due to its altitude and the risk of volcanic eruption.