The condition of Parrikar, diagnosed with advanced pancreatic cancer in February last year and in and out of hospitals in Goa, Mumbai, Delhi and New York since then, had turned "extremely critical" on Sunday, the Chief Minister's Office tweeted earlier in the day.

His last rites will be held here on Monday evening, an official statement said.

Parrikar's body will be kept at the Bharatiya Janata Party state headquarters here, as well as at a state government-operated arts and culture centre all through the morning and afternoon, for public to pay their final respects, before being taken to the Miramar beach for cremation at 5 p.m., according to a statement from the CMO.

In view of the sitting Chief Minister's death, the state government has declared seven-day mourning. The state education board has also postponed the Higher Secondary School Certificate examination earlier scheduled on Monday (March 18) to March 27 in view of the state holiday.

The Central government has announced national mourning on Monday and the national flag will fly at half-mast all across the country. A state funeral will be accorded to Parrikar, who was a former Defence Minister too.

President Ram Nath Kovind was among the first to pay tributes, terming Parrikar an "epitome of integrity and dedication" and whose services to people of Goa and of India will not be forgotten.

Prime Minister Narendra Modi remembered Parrikar, who was among the first BJP leaders to propose him for Prime Minister, as "builder of modern Goa" and that the county would be "eternally grateful" to him for his tenure as Defence Minister.

"When he was Raksha Mantri, India witnessed a series of decisions that enhanced India's security capacities, boosted indigenous defence production and bettered the lives of ex-servicemen," Modi tweeted.

Union Finance Minister Arun Jaitley, who held the defence portfolio before and briefly after Parrikar, also expressed his grief in a tweet, hailing the man as someone who was loved by all.

"Saddened to know about the demise of senior BJP leader Shri Manohar Parrikar ji, Chief Minister of Goa. He always led by example in his public life and was loved by masses. He will be missed by everyone of us. May God render peace to the departed soul. Om Shanti," he wrote.

Defence Minister Nirmala Sitharaman praised Parrikar for the work he did to modernise the armed forces and turning them into "mean fighting machine".

"Shri Manohar Parrikar is no more. A sincere, honest and sensitive political activist. Was simple and down to earth, I learnt a lot from Shri Parrikar. As Raksha Mantri his contribution to making the armed forces a modernised, lean and mean fighting machine will remain unparalleled," she said on Twitter.

BJP President Amit Shah championed the departed as a "true patriot".

"Extremely saddened by the untimely demise of my good friend Manohar Parrikar ji. An epitome of impeccable integrity, a down to earth personality, the first IITian to become CM of a state, great son of India gone too soon... RIP my dear friend...," Union Minister Suresh Prabhu said in a tweet.

Other leaders, cutting across party lines, mourned his death.

"I am deeply saddened by the news of the passing of Goa CM, Shri Manohar Parrikar Ji, who bravely battled a debilitating illness for over a year. Respected and admired across party lines, he was one of Goa's favourite sons. My condolences to his family in this time of grief," tweeted Congress President Rahul Gandhi.

Congress General Secretary Priyanka Gandhi tweeted, "My condolences to the bereaved family of Shri. Manohar Parrikar. I met him only once, when he graciously visited my mother at the hospital two years ago. May his soul rest in peace."

State Congress president Girish Chodankar said that the "passion and enthusiasm" with which Parrikar took on responsibilities either as Leader of Opposition as well as Chief Minister and Defence Minister will be long remembered by the people of Goa.

West Bengal Chief Minister Mamta Banerjee and her Karnataka counterpart H.D. Kumaraswamy also condoled his death.

Goa Archbishop Filipe Neri Ferrao recalled that Parrikar often sought out influential Catholic church leaders for opinions before taking "far-reaching decisions" for the benefit of Goa.

The first Bharatiya Janata Party leader to be Goa Chief Minister, Parrikar headed the state from 2000-05 and 2012-14, before joining the Narendra Modi government as Defence Minister from 2014.

The country's first Indian Institute of Technology alumnus to serve as Chief Minister of a state, he assumed the mantle on four occasions from 2000, but could not complete a single full term in office.

He returned to state politics in 2017 to lead a coalition government headed by the BJP and continued in office despite his protracted illness and criticism from the Opposition and civil society, which had repeatedly demanded his resignation on health grounds.

A widower, Parrikar is survived by his sons, Utpal and Abhijat, their wives and a grandson.