The ongoing nationwide mega-combat exercise of the Indian Air Force (IAF) began in Uttarakhand's Uttarkashi district on Tuesday to examine the strategic preparedness of its infrastructure in the area.

Though IAF officials maintained a distance from the mediainfo-icon, sources said the exercise -- 'Gagan Shakti' -- began around 6.30 a.m. at Chinyalisaur town, 230km from the Indo-Chinainfo-icon border.

The first An-32 transport aircraft carrying IAF personnel landed at the Chinyalisaur airstrip around 7.15 am. The aircraft made a second landing at the airstrip at 7.45 am and a third at 8.01 am, the sources said.

The exercise would continue in Chinyalisaur till Sunday, it added.

'Gagan Shakti' is said to be the IAF's biggest such exercise in decades, to check its operational preparedness with a focus on dealing with all possible security challenges, including from China and Pakistaninfo-icon.

The two-week drill started on April 8 and would continue till the 22nd of this month, officials had said.

Last Saturday, the IAF conducted a maritime air operation in the western sea board to check its deep strike capability in the Indian Ocean Region and beyond.