In view of the alert, the police had barricaded the entry points of eight radials leading to Connaught Place with buses, sources said.
Some gaps were left for the pedestrians to pass through.
This had been done to ensure that even if a vehicle tried to enter into the area it would end up ramming these empty buses, they added.
A man had recently ploughed a van into a crowd of people leaving after offering prayers at a mosque, injuring 11 people near Finsbury Park mosque, north London.
More From This Section
A three-tier security layer was thrown around the area, a senior police officer said, adding, snipers were also stationed on certain buildings to keep a hawk-eye vigil.
Police had received a specific input about a "London- style" attack being planned to disrupt the event that was attended by various dignitaries-- NDA's presidential candidate Ram Nath Kovind, Union Minister M Venkaiah Naidu and Delhi Chief Minister Arvind Kejriwal-- among others.
In April, a hijacked beer truck rammed pedestrians at a central Stockholm department store, killing four people, wounding 15 others and sending screaming shoppers flee in panic.