The leader of Pakistan's alliance for Restoration of democracy, suffered a severe heart attack two days ago, CNN reported.
Khan, a veteran of 50 years in Pakistani politics, was a longtime opponent of the role of the military which has mostly ruled the country since it was formed in 1947 after the partition of India. He spent more than 12 years in jail, CNN said.
He traveled to London and Jeddah in recent weeks to meet with the exiled Pakistani leaders Bhutto and Sharif.
Khan will be buried Sunday in his home town Khangarh in Punjab province.
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