ITANAGAR/ NEW DELHI (PTI): A massive day-night search for a transport aircraft of the Indian Air Force, which went missing two days ago, continued on Wednesday despite inclement weather conditions in mountainous Mechuka in Arunachal Pradesh's West Siang district.

The Russian-origin AN-32 aircraft with 13 people on board lost contact on Monday afternoon after taking off from Jorhat in Assam for Menchuka advanced landing ground near the border with China.

IAF spokesperson Group Capt. Anupam Banerjee said the search and rescue operation has been intensified and expanded despite challenges being posed by vegetation, inhospitable terrain and poor weather in the area.

He said all leads from airborne sensors are being closely assessed and being followed-up with search by aircraft and ground teams.

"Search operation by IAF and Indian Army helicopters was adversely affected by weather during the day today. However, supported by Indian Army, Indian Navy, police and state administration, the search efforts by ground teams and airborne sensors will continue through the night," he said.

Additional assets including two Sukhoi-30 aircraft were deployed on the third day to locate the missing plane apart from the fleet of C-130J and AN-32 planes and two Mi-17 and two ALH helicopters, IAF sources said.

The ground forces included troops from the Army, Indo Tibetan Border Police and state police.

The two Sukhoi-30 and two C-130J aircraft will carry out night missions, they said.

The IAF has been regularly updating the families of all air-warriors on board the aircraft about the rescue operation.

Military sources said rescuers have not received any signal from the emergency locator beacon in the missing plane, adding there is a possibility that the device may not have been functional.

They said the plane that went missing is yet to be upgraded with latest avionics and radars, though some of the AN-32 were strengthened with advanced systems.

The Indian Navy's P-8I aircraft was deployed on Tuesday as it has electro-optical and infra-red sensors which could be helpful in the search operation.

IAF officials said ISRO's Cartosat and RISAT satellites are taking images of the area around Menchuka to help the rescuers find the plane.

They said the area has thick vegetation and difficult terrain which are making the rescue operation challenging.

The IAF on Monday said the aircraft took off from Jorhat at 12.27 pm for the Menchuka advance landing ground, and its last contact with the ground control was at 1 pm.

A total of eight aircrew and five passengers were on board the aircraft.

The AN-32 is a Russian origin aircraft and the IAF currently operates a sizeable number of it. It is a twin-engine turboprop transport aircraft.

An AN-32 aircraft had crashed near a village in West Siang district of Arunachal Pradesh in June 2009 in which 13 defence personnel were killed.

The aircraft had crashed over the Rinchi Hill above Heyo village, about 30 km from Mechuka advance landing ground.

In July 2016, an AN-32 aircraft went missing while taking off from Chennai for Port Blair with 29 people on board.

The aircraft could not be traced following weeks of massive search operations covering 2,17,800 square nautical miles by multiple aircraft.

Months later, an IAF court of inquiry concluded that it was unlikely that the missing personnel on board the aircraft would have survived the accident.