Four bodies have been recovered and six climbers remain missing after an avalanche struck Broad Peak in Pakistan, one of the world's highest mountains.

The climbing party included influential British-Nepali mountaineer Nirmal Purja and an American climber, according to an alpine organization. Purja is known for his record-setting ascents of 8,000-meter peaks.

Rescue operations are underway on the 8,051-meter peak, though harsh conditions are hampering efforts. The avalanche occurred at high altitude where weather can change rapidly.

Authorities have not released the identities of the missing or deceased beyond Purja and the unnamed American. The incident underscores the persistent dangers of high-altitude mountaineering in the Karakoram range.