The head of Pakistan's ruling coalition has refused to accept the resignations of ministers from the party of former prime minister Nawaz Sharif and aims to persuade it to rejoin their six-week-old government. Nine ministers from Sharif's Pakistan Muslim League (Nawaz)(PML-N), quit the cabinet led by the party of assassinated former prime minister Benazir Bhutto on Tuesday after their leaders failed to reach agreement on the restoration of judges sacked by President Pervez Musharraf in November. But Asif Ali Zardari, Bhutto's widower and leader of the coalition, has told Prime Minister Yousaf Raza Gilani not to accept the resignations and he would persuade Sharif to withdraw them and rejoin the cabinet. “Mr. Asif Ali Zardari said that he was committed to promoting national reconciliation and asked the prime minister not to accept resignations tendered by the PML (N) ministers,” the prime minister's office said in a statement issued late on Thursday. The resignations have fueled fears that the coalition might collapse and plunge the nuclear-armed US ally back into turbulence, though Sharif has assured he would continue to support the government from the outside. Underlining those concerns, ratings agency Standard & Poor's cut Pakistan's sovereign rating on Thursday, citing increasing pressure from expanding budget and trade deficits against a volatile political setting. Analysts say new strains are cropping up within the coalition. On Thursday, Musharraf appointed a new governor for the central province of Punjab, Pakistan's biggest province and the traditional heartland of the political-military establishment, which is also Sharif's power base. The new governor, Salman Taseer, is a veteran member of Bhutto's Pakistan People's Party (PPP) and is widely seen as an old adversary of Sharif. Taseer, who is also seen as close to Musharraf, was appointed governor on the recommendation of the PPP. Unelected governors represent the federal government and traditionally wield significant influence over provincial governments. Sharif's party is highly suspicious of Taseer's appointment with some members seeing it setting the scene for efforts to destabilize the Punjab provincial government it dominates. Differences between the two major parties have renewed talk of a secret deal between the PPP and the unpopular Musharraf and fueled speculation that Zardari is ready to prop up Musharraf if Sharif fails to fall into line. Sharif has threatened to join the lawyers' community and would launch a protest movement to press the government to reinstate the judges Musharraf dismissed after he imposed emergency rule. Zardari says he too wants to reinstate the judges but wants to tie it to a constitutional package of political and judicial reforms. The proposed constitutional changes could sideline the Chief Justice of the Supreme Court, Iftikhar Chaudhary, who has become a rally figure for anti-Musharraf forces after he refused to resign under Musharraf's pressure in March last year. But some analysts said despite the strains, the two major parties would not like to part ways at a time when they are confronting a powerful president.