As many as 15,000 policemen fanned out across New Delhi as an unprecedented security cover was thrown around the capital to prevent terrorist activities as it celebrated the 58th Republic Day.

Stringent security arrangements were in place, mainly along the parade route and around the India Gate area, with special emphasis on tightening access control measures to thwart human bombs.

Securing the Rajpath, the main venue of Republic Day Parade, a multi-layer security ring was in place.

Around 400 armed commandoes from the Delhi police were positioned along the parade route from Vijay Chowk to Red Fort while about 15,000 Delhi police and Army personnel were deployed across the capital.

The police deployed mobile hit teams and anti-aircraft guns as elite NSG snipers and commandoes of the Delhi police and Indo-Tibetan Border Police were posted at strategic locations as part of the massive ground-to-air security apparatus put in place in view of terror threats.

All roads leading to Rajpath were sanitised and major traffic diversions were made to regulate the entry of vehicles into the vicinity of the parade route, while people coming to view the parade had to go through multiple security checks.

All vehicles entering Delhi's borders had to pass through multiple checks.

Elaborate air defence measures, including deployment of anti-aircraft guns, were also made to check the intrusion into the capital's air space, a no-fly zone during the 105-minute parade. Besides, three military choppers maintained air surveillance all along the parade route.

Metro trains passing near the main venue on the Rajpath were also not allowed to operate in the morning.

Patrolling in crowded market areas had been intensified in the run-up to Republic Day, while checking and frisking in Metro, railway stations and bus terminals were stepped up.

Security at the Indira Gandhi International airport was also strengthened in coordination with the Central Industrial Security Force.

The Delhi police had yesterday foiled a major terrorist bid to subvert the national event by arresting a Lashkar-e-Tayiba operative with explosives.

The Pakistan-trained militant, identified as Iftikhar Alam, was arrested from a bus-stand near the Metro station in Seelampur locality of north-east Delhi last evening. Around 2.5 kg of RDX, two detonators and a timer were recovered from him.

In another incident, the police arrested a man carrying a live smoke grenade from the Old Delhi railway station. Mohammed Hussain Sheikh, from West Bengal, was nabbed during a routine check and booked under the stringent Explosives Substances Act.