"Some people say that Pakistan will disintegrate, and that it will be taken over by extremists," Zadari said. "But let me assure you that we will not let this happen. Bhutto's mission to serve Pakistan and uplift their living standards will continue."
Zadari addressed a crowd of thousands near the family mausoleum in Sindh province where Bhutto, his father-in-law, is buried along with former prime minister Benazir Bhutto, Zadari's wife and Bhutto's daughter.
Zulfiqar Ali Bhutto, 51, was hanged at a prison in Rawalpindi on what he had said was a trumped-up murder charge. Benazir Bhutto was assassinated in 2007.
In 1967, Zulfiqar Ali Bhutto founded the Pakistani People's Party, which once again is in power but struggling against increasing militant violence and a sluggish economy, Dawn, Pakistan's English-language newspaper reported Saturday.