Veteran socialist George Fernandes, who was the defence minister in the Atal Bihari Vajpayee government, passed away on Tuesday following prolonged illness, his long-time associate Jaya Jaitly said. He was 88.

Fernandes was suffering from Alzheimer's disease, which had forced him out of the public life, and had recently contracted swine flu, she said, adding that he died at his residence in Delhi.

He was the defence minister in the NDA government when India fought the Kargil war in 1999. It was during his tenure that India conducted nuclear tests at Pokhran in 1998.

He was also the industry minister under the Jan Sangh government which had defeated former Prime Minster Indira Gandhi in 1977.

Tributes poured in for the veteran leader, with Prime Minister Narendra Modi saying he was frank and fearless and never deviated from his ideology. 'A visionary railway minister and a great defence minister who made India safe and strong.... He resisted the Emergency tooth and nail. His simplicity and humility were noteworthy,' Modi said.

Congress chief Rahul Gandhi expressed his condolences to Fernandes' family and friends. 'I'm sorry to hear about the passing away of former Parliamentarian & Union Minister, George Fernandes Ji,' he said in a Facebook post.