India on Wednesday dismissed reports that it had put its Air Force on a state of "high alert" and said nothing unusual or extraordinary has been done.

"It is normal for the armed forces to remain on alert even in normal times," Defence Ministry spokesperson Sitanshu Kar said in Delhi [Images], after reports started circulating that the Indian Air Force was put on an alert in the wake of the November 26 Mumbai terror attacks [Images].

Army, Navy and IAF officers too independently denied reports that their respective headquarters had instructed their units and troops to be on a state of alert or had cancelled leave of personnel to ensure its force levels were high.

"It is a general norm that there cannot be more than 25 per cent personnel on leave, temporary duty or studying a course. At all times, the units have a minimum of 75 per cent of its personnel at their place of posting," the officers said.

And in matters of national security and protecting the country from external threats, the armed forces have to remain alert all 365 days of the year, they said.

However, on the basis of intelligence inputs that there could be a 9/11-type of aerial terror threats pointed out by Defence Minister A K Antony last week, the IAF was prepared to counter any such attacks, they said.

To that effect, the IAF had decided to spruce up its surveillance cover of the national capital region by deploying an Aerostat radar in and around Delhi, apart from strengthening the air defence units all over the country, they added.