Ahmedabad/New Delhi, Aug 30(IANS) : Nine defence personnel, including five officers, were killed Thursday when two Indian Air Force (IAF) helicopters collided mid-air near Jamnagar in Gujarat, an official said.

The collision at the Sarmat range near Jamnagar, about 275 km from Ahmedabad, took place at 12.05 p.m. while two Russian-origin Mi-17 cargo choppers of the air force were on a training mission shortly after taking off from the Jamnagar airbase.

"Two Mi-17 IAF helicopters crashed near Sarmat range in Gujarat Aug 30 at about 12.05 p.m. The helicopters had taken off from Jamnagar airbase and were on a routine flying training mission. There were nine personnel on board and all succumbed to injuries," IAF spokesperson Wing Commander Gerard Galway said in a statement in New Delhi.

"An inquiry has been ordered to investigate the cause of the accident," he said.

On board the ill-fated choppers were five officers and four men of other ranks, sources said.

However, the names of the deceased are being withheld till the next of kin are informed.

The choppers, according to information reaching New Delhi, were flying close to each other when their rotor blades came in contact, causing the accident.

The training mission involved flying at such proximity, said IAF officers.

Defence Minister A.K. Antony expressed deep sorrow at the incident and conveyed condolences to the bereaved families in a statement.