Security agencies in India are on high alert with reports that terrorist groups could be planning an airborne attack during celebrations to mark Republic Day.
A security blanket is in force across central New Delhi, the site of the major celebrations for the event.
Anti-aircraft weaponry was put in place after reports the Lashka-e-Toiba group has acquired paragliding equipment which could be used to launch an airborne assault.
The ABC reports up to 15,000 police and security officers are deployed across the city to guard the day's main event - a military parade through the centre of New Delhi.
Aerial and sea patrols have been increased in Mumbai, the scene of the November 2008 terrorist attacks.
Republic Day marks India's transition from a British dominion to a republic.
