Hyderabad, Sep 2 - Andhra Pradesh Chief Minister Y.S. Rajasekhara Reddy's fate appeared uncertain Wednesday night, 12 hours after a helicopter carrying him went missing, even as a Sukhoi SU-30MKI combat jet of the Indian Air Force (IAF) and a low-flying aircraft of the National Remote Sensing Agency (NRSA) began search operations that were expected to continue till late into the night.

The army, the air force and paramilitary forces, as also the police and civil authorities, were continuing the massive search operations through the night, even as the Indian government is trying to seek assistance from the US Defence Department to obtain real time satellite imagery of the area in which the helicopter is believed to have gone down.

After the search by eight helicopters was called off after sunset, the SU-30MKI combat joined the special NRSA aircraft in continuing the search through the night.

The SU-30 has night vision capabilities while the NRSA aircraft can fly at a height of 1.25 km and scam an area of 250 sq km at a time.

'Due to its better imagery and night vision capabilities, a Su-30 MKI has been pressed into service. It can look through the cloud and foliage cover in the area,' an IAF spokesman said in New Delhi.

'Four helicopters had been deployed today (Wednesday) for the rescue mission. The search has been called off due to bad light and the choppers will again hit the skies at first light tomorrow (Thursday),' the spokesman added.

Andhra Pradesh Chief Secretary P. Ramakant Reddy told reporters in Hyderabad that the chief minister's helicopter was last seen by some villagers between 9.15 a.m. and 9.30 a.m. between Atmakur and Bandi Atmakur in Kurnool district. 'After 9.45 a.m. we lost radio contact. It is presumed that from Kurnool, it was crossing the Nallamalla forests towards Prakasam district,' he added.

He said the army had joined the search operations on the ground. About 5,000 paramilitary personnel were also heading towards the forests. Since Nallamalla is considered a Maoist stronghold, the elite Greyhounds anti-Maoist force, along with Andhra Pradesh special police and state police personnel are conducting the search operations.

The chopper carrying YSR, as the 60-year-old chief minister is known, his special secretary Subrahmanyam, his chief security officer A.S.C. Wesley and two pilots, took off 8.35 am from Hyderabad and was headed for Chittoor, 588 km away and close to Tamil Nadu.

'Let us hope for the best. Let us pray for the best,' Home Minister P. Chidambaram said in New Delhi of the rescue operations.

A sombre Chidamabaram said the search by the IAF was called off late in the evening 'because of the weather and failing light' but said the manual search for the chopper would go on 'at least for a few hours' before resuming at first light.