"She fought for secularism and against those who wanted to divide society on religion and caste lines," she further added.
"She can never be erased from the pages of history," former President Pranab Mukherjee said.
Earlier in the day, former PM Manmohan Singh and Congress VP Rahul Gandhi paid tribute to Indira Gandhi.
Prime Minister Narendra Modi on Sunday also paid tributes to Indira Gandhi on her 100th birth anniversary.
Gandhi was born on this day in 1917 in Allahabad.
"Tributes to former PM Mrs Indira Gandhi on her birth anniversary," the Prime Minister tweeted.
(With inputs from agencies)