"My heartfelt condolences to the family and followers of Moulvi Iftikhar Ansari. His untimely demise has left a void that will be long felt," Omar wrote on micro-blogging website Twitter.
Ansari, a four-time MLA from Pattan Assembly segment, passed away in the wee hours today at his Qammarwari residence following prolonged illness.
"Moulvi Sahib has cast a long shadow with his contribution as a religious leader and as a public representative, which will be long remembered," he added.
Omar also expressed solidarity with the followers of the late religious leader and conveyed his condolence to them in this hour of grief.
Political Secretary to the Chief Minister, Tanveer Sadiq was accompanying Omar.