Family sources said he was ailing for quite some time.
He was a firebrand politician and a learned Shia scholar. His death is being widely mourned in Jammu and Kashmir by people cutting across religious, sectarian and political affiliations.
Chief Minister Omar Abdullah was among the first to reach the late leader’s uptown Qamarwari residence in Srinagar when he heard of the news.
Ansari began his political career in late 1970s when he contested the Lok Sabha election from Srinagar constituency against National Conference founder Sheikh Muhammad Abdullah’s widow Begum Sheikh Muhammad Abdullah.
He lost the election, but was credited for starting the culture of genuine mainstream political opposition in Kashmir.