Shimla: In the seventh crash involving IAF's fighter planes this year, a MiG-29 aircraft crashed in a mountainous region in Himachal Pradesh's Lahaul-Spiti valley during a night flying exercise but the fate of the pilot is not known.

The mishap over a forest area occurred at 8.30 pm last night in Chokang valley, 400 kms from here, Indian Air Force (IAF) officials said on Wednesday.

In a massive rescue operation, IAF deployed seven aircraft including two Su-30 MKI fighters for searching the pilot and the wreckage of the ill-fated aircraft in the second crash of its warplane this month.

The search and rescue mission was called-off after sunset this evening and will resume tomorrow at first light.

Local villagers in the tribal area said they heard a loud blast and the sky was lit briefly around the same time when the crash took place.

"Two Su-30MKI fighter jets from Bareilly were launched for searching the pilot and the exact location of the crash. Two An-32 transport aircraft were also deployed for the mission from Chandigarh, but so far there is no trace of the aircraft or its pilot," an IAF spokesperson said in New Delhi.

A Dornier surveillance aircraft, Cheetah and Chetak helicopters were also pressed into service.

Two MiG-29 aircraft of IAF's Western Air Command took off from Adampur air base near Jalandhar for night flying exercise in high altitude and during a turn, one of them crashed into a mountain, officials said.

Lahaul-Spiti's DSP Khajana Ram said that they were informed about the crash at 11 PM last night and the rescue teams had reached the area by 3 AM. "As it is a high altitude area, we are facing difficulty in locating the wreckage," he said.

The IAF said the second plane returned safely and the exercise has not been called off.

This is the seventh air crash involving IAF's fighter aircraft this year and the second this month. While most of the pilots flying these aircraft managed to eject safely, two pilots lost their lives. On October 7, a MiG-21 aircraft crashed near Uttarlai airport in Rajasthan's Barmer district but the pilot ejected safely.

It could not be ascertained where the aircraft fell after the crash. There are deep valley and gorges in the tribal areas and it was possible that the wreckage had sunk into the ravines.

The choppers were used to sweep out a wider area in the forest at various altitudes and the entire search and rescue team is on standby to locate the wreckage and the pilot, the IAF spokesperson said. They were flown for around two hours.

Deputy Commissioner Rajiv Chandra and SP Vimal Gupta were also involved in the search operations.

Rajiv said it was possible said that the crash might have occurred in adjoining Pangi and Bharmaur tribal areas.