Ten other members of the team survived the avalanche but many were injured and are being flown to hospitals by rescue helicopters, he said.
Weather conditions were deteriorating and it was not possible to continue air searches of the mountain on Sunday, Kuwar said.
The identities of the victims were still being confirmed.
The avalanche hit the climbers at a camp at 7,000 meters (22,960 feet) as they were preparing to head toward the summit, which is 8,156 meters (26,760 feet) high.
It is currently the beginning of Nepal's autumn mountaineering season.