ISLAMABAD: President Asif Ali Zardari on Saturday chaired crisis talks with Pakistan's ruling party on how to prevent his government unravelling after a court scrapped an amnesty on corruption charges.

In a bid to head off what could be the worst political crisis of his troubled 15 months in power, the president convened the central executive committee of the Pakistan People's Party (PPP) in the capital Islamabad.

The Supreme Court's move to annul a decree protecting more than 8,000 people, including Zardari and top allies, from corruption charges, has been welcomed by a public increasingly fed up with the government.

But the fallout threatens to seriously distract the coalition from multiple offensives against Taliban militants, rising extremist attacks and mounting US pressure to cooperate more in the war in neighbouring Afghanistan.

A court has summoned Interior Minister Rehman Malik over re-opening a corruption case and officials banned Defence Minister Ahmed Mukhtar from leaving the country on an official visit to close ally China.

Pakistan's anti-corruption National Accountability Bureau (NAB) has called for travel bans on 253 people since Wednesday's court ruling, sparking calls for Zardari to resign and rattling the US-backed government.

Prime Minister Yousuf Raza Gilani has ordered an inquiry into why Mukhtar was banned from travelling, and suspended the top civil servant at the interior ministry, a director at the Federal Investigation Agency and two inspectors.

"The party would like to take into account the point of view of its members, their suggestions and the strategy that the government should adopt," said PPP spokeswoman Fauzia Wahab.

Zardari is immune from prosecution as president, but his eligibility for office could be challenged because corruption cases were pending against him when the amnesty was adopted. Cabinet ministers have no such immunity.

Pakistan is ranked the world's 40th most corrupt country by global watchdog Transparency International and many governments have fallen as a result of military intervention over accusations of graft.

Gilani himself spent five years in jail while military ruler Pervez Musharraf was in power on charges of misusing his authority while speaker of the national assembly in proceedings widely seen as politically motivated.

Analysts are divided on the options open to Zardari. Some believe the government should sack the implicated ministers to restore public confidence but others predict that the government will close ranks and fight.

"They will campaign on three grounds -- that a conspiracy is being hatched, that the establishment never accepts the PPP in power and that the judiciary is being used as an instrument to destabilise the government," said Rasool Bakhsh Raees, political science professor at Lahore University of Management Sciences.

"I believe that a tussle between the government and the judiciary has started... This does not mean the PPP is dying," Raees said.

Besides summoning the interior minister to appear in court, the anti-corruption bureau has reopened cases against 52 other people -- cases frozen when the amnesty was passed in 2007, said one senior official.

Politicians, bureaucrats, ex-military officers and diplomats are on an "exit control list" restricting travel, some arrest warrants have been revived and properties re-frozen, say NAB officials.

The amnesty -- called the National Reconciliation Ordinance -- was passed in October 2007 by Musharraf.

It allowed politicians including Zardari and his wife, ex-prime minister Benazir Bhutto, who was killed two months later -- to stand for office.

Zardari's PPP went on to win elections in 2008, restoring civilian rule, but his relations with the powerful military are strained and his public approval ratings at rock-bottom.

Pakistan said Saturday that 12 militants were killed in fighting in the northwest, six in Khyber and six in South Waziristan -- part of the tribal belt on the Afghan border which Washington calls the most dangerous region on Earth.