With reports that terrorists might use a plane or some other flying object to strike on Republic Day, several Indian Air Force airbases will be on high alert on January 26, defence sources said on Friday.

At least eight airbases will keep two jets each in readiness, the sources said.

The IAF and the army will also set up observation posts at airports in Delhi, Mumbai, Kolkata, Ahmedabad and Chennai, the sources said.

In Delhi, where the country's main parade will be held and watched by the nation's entire leadership, special measures have been initiated, Special Commissioner of Delhi Police [Security] S K Kain said.

At least 24 air defence guns and the same number of medium machine guns will be positioned at several strategic places across the capital, the sources said.

Two IAF helicopters with one assistant commissioner of Delhi police each on board will hover over the capital's skies during the parade from Vijay Chowk to Red Fort.