Islamabad: Top leaders of the ruling Pakistan People's Party on Friday  questioned the Supreme Court's decision to set up a commission to probe the controversial secret memorandum sent to the US military, saying only the executive had the power to appoint such a panel.

PPP lawmaker Babar Awan, a close aide of President Asif Ali Zardari, expressed disappointment at the order issued by the apex court and said only the executive had the constitutional authority to appoint a commission to investigate matters like the "Memogate" controversy.

Addressing a news conference this evening with Information Minister Firdous Ashiq Awan, Religious Affairs Minister Khurshid Shah and PPP spokesman Qamar Zaman Kaira, Awan contended that the apex court had issued its order without giving the federal government an opportunity to present its views.

The government will never allow anyone to exercise executive authority or undermine the supremacy of parliament, Awan said.

Observers noted that the stand adopted by the PPP could possibly set the stage for a confrontation between the beleaguered government and the judiciary led by independent-minded Chief Justice Iftikhar Chaudhry.

Earlier in the day, the apex court ordered the formation of the commission to probe the Memogate issue in response to nine petitions seeking an investigation into the matter. One of the petitions was filed by PML-N chief Nawaz Sharif.

The court sought responses within 15 days from persons named as respondents in the petitions, including President Zardari, army chief Gen Ashfaq Parvez Kayani and Inter-Services Intelligence chief Lt Gen Ahmed Shuja Pasha.

Pakistan's former envoy to the US, Husain Haqqani, was forced to resign after Pakistani-American businessman Mansoor Ijaz made the memo public last month.

The memo had sought US military help to prevent a military takeover in Pakistan in the wake of the raid that killed Osama bin Laden in May.

The memo also committed the Pakistan government to wide-ranging changes in its national security set-up, including the removal of military officials believed to have links to militants.

During the news conference, Awan contended that former envoy Haqqani, who had returned to Pakistan to clear himself of the charges levelled against him, too was not heard by the apex court.

"He will be in the country until he is exonerated from this charge and the PPP has a history of facing charges in the court of law within constitutional limits," he said.

Awan questioned former premier Sharif's motives for filing the petition, saying it was a direct assault on democracy.

He said the court had acted even before the 17-member bicameral parliamentary committee on national security had begun its investigation into the memo.

He claimed Sharif was working at the behest of someone else to declare an elected president a "traitor".

He said, "Nawaz Sharif has attacked democracy while hiding behind a national institution".

Awan also questioned the composition of the nine-judge bench hearing the memo case, saying certain judges were biased.

He claimed the judiciary had extended undue relief to Sharif and his brother, Punjab Chief Minister Shahbaz Sharif.