A Junior Commissioned Officer (JCO) and eight jawans were killed after the truck they were travelling in skidded off the road and fell into a river in Ladakh, the army said.
The accident happened in Kiyari, 150 km from Leh, at 4.45 pm, Senior Superintendent of Police in Leh PD Nitya told news agency PTI.
The officer said one more jawan is undergoing treatment and his condition is said to be "critical".
A divisional headquarters of the Indian Army is based at Kiyari in eastern Ladakh.
Officials said 10 soldiers were travelling in the truck and there were five vehicles in the convoy.
After the accident, a police team rushed to the spot and took all the injured soldiers to an army medical facility, where eight of them were declared dead. Another jawan died subsequently.
Prime Minister Narendra Modi in a post on X, formerly Twitter, gave his condolences to the bereaved families.
"Pained by the mishap near Leh in which we have lost personnel of the Indian Army. Their rich service to the nation will always be remembered. Condolences to the bereaved families. May those who are injured recover at the earliest," PM Modi posted.
Defence Minister Rajnath Singh said that country will never forget their exemplary service.
"Saddened by the loss of Indian Army personnel due to an accident near Leh in Ladakh. We will never forget their exemplary service to our nation. My thoughts are with the bereaved families," Mr Singh posted on X, formerly Twitter.
He said that the injured personnel have been rushed to the field hospital. "Praying for their speedy recovery," Mr Singh added.