Agus said that the plane serving Malang air forces base departed from Halim Perdanakusumah airport in Jakarta early Tuesday morning and made stopovers in Pekanbaru, Riau and Dumai to pick up troops to be transferred to other regions.

He said that the plane was on its route to transport logistics and personnel to Tanjung Pinang and Natuna islands.

An official at Indonesia's Search and Rescue (Basarnas) Medan branch told Xinhua earlier in the day that manifest of the crashed plane indicates that the plane was boarded by 55 persons. That figure did not include 12 plane crews operating the ill-fated plane.

According to Agus, the plane's pilot asked for RTB (Return to Base) procedure to air traffic control officers before the crash, which happened shortly before noon. He said the request suggested that a problem has occurred in the plane. Indonesian military has set up a team to investigate the plane crash.

Agus said the plane was manufactured in 1964 and served the air forces' 32 Squadron based in Malang, East Java. Indonesia is the largest operator of C-130 Hercules in the southern hemisphere with 28 such planes in service at the moment.