In a condolence letter to Pant's wife Ila, the Prime Minister said the country has lost an eminent public figure and an able administrator.
"I was deeply saddened to learn of the passing away of your husband Shri K C Pant. Shri Pant served our country and people with great distinction in his long political career," Singh wrote in the letter.
Expressing his "deepest condolences" to the family, Singh said, "He (Pant) distinguished himself as a Member of Parliament and as a Minister in the Union Council of Ministers holding important portfolios like Home, Defence and Finance."
"On this sad occasion, I convey my deepest condolences to you and other members of the family. I pray for the departed soul," Singh added.
Defence Minister A K Antony in his message expressed "profound grief" at the sad passing away of Pant, who was the Defence Minister from 1987 to 1989.
Stating that Pant's contribution will be fondly remembered, he said, "Pant steered the Ministry at one of the most critical junctures of history as the Indian Peace Keeping Forces (IPKF) was deployed in Sri Lanka as a stepping stone to the tortuous journey for peace in the island nation."
Referring to the Operation Cactus conducted by Indian armed forces in Maldives, he said, "The Indian troops were also deployed at short notice in Maldives to abort a coup attempt, in a clear manifestation of our commitment to the promotion of peace and stability in South Asian Region."
81-year-old, who was ailing for some time, breathed his last at 8:30 AM today.
