An Indian soldier shot dead five colleagues before turning the gun on himself on Thursday, officials said.
The incident took place in the early hours at a military camp in the India-controlled portion of Kashmir.
"One of the army men ran amok and fired indiscriminately at his colleagues inside an army camp at Safa Pora," army spokesman Lieutenant Colonel N N Joshi said of deaths in the northern Ganderbal region
"Five army men died on the spot and one was injured. The army man later shot himself dead using his service rifle," he said.
Joshi said the army has ordered an inquiry.
A senior army officer who declined to be identified said initial investigations suggested the shooter was under stress.
There were 635 cases of suicide or attempted suicide in the armed forces from 2003 to 2007, all "attributable to increased stress environment leading to psychological imbalance in the soldiers", a parliamentary committee said in a 2010 report.
Several rebel groups have been fighting since 1989 for Kashmir's independence from India or its merger with neighbouring Pakistan.
Though rebels have largely been suppressed, India still maintains over half a million soldiers in Kashmir, many along the frontier with Pakistan, but plenty more in towns and villages.
Additional reporting by agencies