Pakistan's main opposition party has called for Asif Ali Zardari, the country's president, to resign after the supreme court declared void an amnesty deal protecting him from corruption charges.

Following the ruling, officials from the Pakistan Muslim League-N (PML-N) said Zardari should be obliged to step down.

"It will be in his own interest, it will be in the interest of his party and it will be good for the system," said Khawaja Asif, a senior leader PML-N leader.

Siddiqul Farooq, a spokesman for the party, said: "President Asif Ali Zardari should resign on moral grounds and should not depend upon the crutches of the constitution."

Pakistan's constitution guarantees Zardari immunity while in office.

Resignations demanded

But the constitution also states that presidential candidates must be pious, honest and truthful and not have been convicted in a criminal case.

The supreme court's decision on Wednesday declaring  the amnesty agreement as being unconstitutional paves the way for corruption cases against Zardari and thousands of other officials covered by the amnesty to be revived.

"All the cabinet members must immediately tender their resignations," Farooq said.

Beneficiaries of the amnesty include Pakistan's interior and defence ministers.

A number of cases were pending against Zardari when it was announced by Pervez Musharraf, then Pakistan's president, that he and others would be immune from prosecution under the 2007 National Reconciliation Ordinance (NRO).

Musharraf declared the NRO while under pressure to hold elections and end eight years of military rule.

Amnesty deal

Although Zardari has spent years in jail over corruption charges, he alleges the charges were politically-motivated and questions hang over whether he was ever actually convicted.

Zardari's Pakistan People's Party (PPP) won elections in 2008, restoring civilian rule, but the NRO expired at the end of last month and the PPP did not have enough support to renew the ordinance in parliament.

Senior figures in the PML-N, led by Nawaz Sharif, a former prime minister, have already called on Zardari to give up powers inherited from Musharraf such as those to sack the prime minister and dissolve parliament.

PHOTO CAPTION

Asif Ali Zardari addresses a meeting in Islamabad on December 1, 2009.

Al-Jazeera