"Shocked & deeply saddened to hear of Asma Jehangir's sudden death".
She also served as the head of nonprofit Human Rights Commission of Pakistan.
Asma Jahangir was born on January 27, 1952.
An active member of bar politics, she was the first female president of the Pakistan Supreme Court's Bar Association.
Punjab Chief Minister Shahbaz Sharif tweeted: "Pakistan has lost a passionate champion of human rights and a staunch supporter of democracy..."
The firebrand human rights activist graduated from Kinnaird College and later pursued an LLB from Punjab University.
She was repeatedly threatened by the country's militant religious right, whom she criticized loudly and often.
"She has fought against the military dictators and also for the rights of downtrodden individuals".
She had always been a very vocal critic of the human rights violations in the country, besides widely popular for taking up court cases of marginalized segments of the society.
She was imprisoned in 1983 for her pro-democracy activities during General Zia ul-Haq's military rule and put under house arrest in 2007 for opposing President Pervez Musharraf's removal of the Supreme Court's chief justice.
Her family was threatened and her driver was beaten up in 1995 for her daring to defend a 14-year-old Salamat Masih who on the accusation of blasphemy.
She said Pakistan should first take up the issue of capital punishment through unfair trials here and of those Pakistanis who were being consistently executed in Saudi Arabia and then show disproportionately high passion for the politicians of Bangladesh.
Moreover, her daughter, broadcast journalist Munizae Jahangir shared on Twitter that the family is awaiting relatives to return to Lahore before the funeral can be held. She gained global acclaim for being the voice of conscience in a country where liberal, secular voices have been continuously under threat.
"Asma Jahangir was a voice of the oppressed and an icon of courage and valour", said Maryam Nawaz Sharif, the daughter and political heir of former prime minister Nawaz Sharif.
"She was and will remain an inspiration".
She has received several awards, including a Hilal-i-Imtiaz and a Sitara-i-Imtiaz in 2010. She was most unwanted person by establishment of Pakistan during all marial Laws but she never compromised or bowed down against dictatorial rules.