Musharraf returned to Pakistan last weekend after four years of exile despite threats of death and arrest. He resigned five years ago while facing impeachment. He gained power through a coup in 1999.
He has said he aims to lead the All Pakistan Muslim League party in May elections.
Government officials said Musharraf would be arrested upon returning to Pakistan but party members have taken pre-emptive measures.
Pakistan director for Human Rights Watch Ali Dayan Hasan said Musharraf needs to face justice for a legacy of abuses, including forced disappearances of his opponents in Baluchistan province.
"Only by ensuring that Musharraf faces the well-documented outstanding charges against him can Pakistan put an end to the military's impunity for abuses," Hasan said in a statement from New York.
Musharraf was escorted Sunday from Karachi airport. Members of the Taliban threatened to kill him once he returned to the country, CNN reported.
A U.N. report on the 2007 assassination of former Prime Minister Benazir Bhutto implicates Musharraf, claiming Pakistani officials at the time "failed profoundly" to protect her.
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