Rescue teams have recovered four bodies from the site of an avalanche on Pakistan’s Broad Peak as the search continues for six other climbers who remain missing, officials said Friday.

Authorities said efforts to retrieve the bodies were ongoing despite severe weather conditions that have complicated rescue operations and limited the use of military helicopters.

Senior government officials, speaking on condition of anonymity because they were not authorized to comment publicly, said the identities of the four victims had not yet been confirmed.

Adverse weather continued to hinder search efforts throughout Friday, according to a statement issued by Gilgit-Baltistan Chief Minister Amjad Hussain.

The climbers disappeared after an avalanche struck Broad Peak while they were attempting to summit the 8,051-meter (26,414-foot) mountain in Pakistan’s Karakoram range.

Karrar Haidri, vice president of the Alpine Club of Pakistan, said the group lost contact with its base camp shortly after the avalanche.

“The team has been out of communication since Thursday,” Haidri said, adding that Pakistan Army helicopters were assisting in the search-and-rescue mission whenever weather conditions allowed.

According to the Alpine Club of Pakistan, the expedition included five climbers from Nepal, Pakistani mountaineer Sohail Sakhi, an Omani climber identified as Nathira, American climber Mallory Geis, a Chinese climber identified only as Wang, and another foreign climber whose identity has not been released.

Meanwhile, China’s Foreign Ministry said on Friday that it was working to verify whether one of its citizens was among those reported missing.

Broad Peak, the world’s 12th-highest mountain, is one of Pakistan’s most challenging peaks and attracts experienced mountaineers from around the world. However, unpredictable weather, avalanches and extreme terrain continue to make climbing in the Karakoram one of the most dangerous pursuits in high-altitude mountaineering.