Pakistan's new government plans to try former military ruler Pervez Musharraf for treason.
Prime Minister Nawaz Sharif told the Pakistani parliament: "He will have to answer for his guilt before the court."
Pakistan's powerful armed forces are expected to be angered by the move against the former general, which could be seen as an attempt to stand up to a military that has ruled Pakistan for much of its 66-year history.
The charges relate to Musharraf's 2007 declaration of a state of emergency and the subsequent suspension of constitutional rights.
Musharraf came to power after ousting Sharif in a coup 14 years ago, then chased him into exile in Saudi Arabia.
Musharraf remains under house arrest, having returned to Pakistan from self-imposed exile earlier this year.
His spokesperson described the proposed move as "reckless and ill-conceived".
In Pakistan, treason carries the death penalty.
The government stopped short of declaring officially that it was filing charges against Musharraf, saying it would first consult with other political parties.
Sharif cited the Supreme Court's decision that Musharraf committed treason under Article 6 of the Constitution by imposing a state of emergency. He told parliament:
"The prime minister is under oath to protect, preserve and defend the constitution."