Prime Minister Narendra Modi paid tribute at the 'Amar Jawan Jyoti', the memorial dedicated to martyrs on the 66th Republic Day here on Monday.
U.S. President Barack Obama, who is on a three-day visit to India, will be chief guest at the Republic Day parade.
Security arrangements have been beefed up across the capital due to the same.
Earlier on Sunday, President Obama and his wife Michelle landed in the national capital, where they were received by Prime Minister Modi.
President Obama will be the first U.S. president to attend the Republic Day celebrations tomorrow and is also the first U.S. president to visit the country twice while in office.