The Indian Air Force on Thursday said the search operation to locate a missing AN-32 aircraft has been intensified with more assets. Two Cheetah helicopters will join the search operations on Friday while local civic volunteers and the police have been roped in as well, the Air Force said

The transporter aircraft, with 13 people on board, went missing 33 minutes after taking off from Jorhat in Assam on Monday. It was heading to Menchuka in Arunachal Pradesh, near the China border.

“IAF Missing AN-32 search continues,” the Air Force said on Twitter. “The area of search has been expanded [and] more assets including smaller [and] more manoeuvrable helicopters like cheetah have been included in the rescue mission so as to approach areas inaccessible by bigger helicopters or individuals on foot.”

The Navy said a Long Range Maritime Reconnaissance aircraft P8i reached the search area at 8 am Friday to assist in the operations.

On Tuesday, the Navy and the Indian Space Research Organisation joined the search. While the Navy deployed a long-range maritime reconnaissance aircraft, the space agency pressed into service its RISAT series of radar-imaging satellites. IAF officials said the ISRO’s Cartosat and RISAT satellites were capturing images of the area.

The Indian Air Force on Wednesday said it had intensified and expanded the search operation “despite challenges posed by vegetation, inhospitable terrain and poor weather”. However, the search-and-rescue operation has met with little success so far.

On Thursday, the Air Force deployed four Mi-17 helicopters, three Advanced Light Helicopters, two Sukhoi-30 aircraft, one C-130 transporter aircraft and one Army’s Unmanned Aerial Vehicle.

In 2016, an Indian Air Force AN-32 plane had disappeared while flying over the Bay of Bengal after taking off from Chennai for the Andaman and Nicobar Islands. The aircraft was never found, and all 29 people on board were presumed dead.