Union minister Ram Vilas Paswan, who recently underwent a heart surgery, died on Thursday at a Delhi hospital where he was recuperating.

The 74-year-old was undergoing treatment at the hospital, and had to undergo surgery "due to the situation that had suddenly emerged," his son Chirag Paswan had tweeted on Saturday, reported ndtv.com and agencies.

"Papa… Now you are not in this world but I know you are always with me wherever you are. Miss you Papa," Chirag Paswan tweeted on Thursday evening.

He shared an old photo of him and his father along with the tweet.

A Dalit leader from Bihar, Ram Vilas Paswan was serving as the Union Minister of Food and Public Distribution in the Narendra Modi government.

An eight-time Member of Parliament in the Lok Sabha, Paswan went to jail during Indira Gandhi's tenure when an emergency was imposed in the country. He began his political career as a member of the Samyukta Socialist Party and in 1969 became a member of the Bihar Legislative Assembly, reported The Indian Express.

Paswan was elected to Lok Sabha for the first time in 1977 as a Janata Party member and was re-elected for five consecutive times from Hajipur constituency in Bihar. He had formed LJP in 2000 and joined Congress-led United Progressive Alliance in 2004.

Paswan had served as a Union Minister under five prime ministers and his party has been a member of all national coalitions. He hailed from Shaharbanni Village in Khagaria District of Bihar. His son, Chirag Paswan currently heads the LJP.

Prime Minister Narendra Modi on Thursday condoled the passing away of Paswan, saying there is a void in the nation that will perhaps never be filled.

Reacting to Paswan's demise, the Prime Minister said, "I am saddened beyond words. There is a void in our nation that will perhaps never be filled."

"Shri Ram Vilas Paswan Ji's demise is a personal loss. I have lost a friend, valued colleague and someone who was extremely passionate to ensure every poor person leads a life of dignity," he said.

Hailing the Lok Janshakti Party patron for his rise in politics through hard work and determination, Modi said as a young leader, Paswan resisted "tyranny and the assault on our democracy during the Emergency".

"He was an outstanding Parliamentarian and Minister, making lasting contributions in several policy areas," Modi said.