The government has decided to withdraw a letter that had been sent to Swiss authorities during Pervez Musharraf's tenure to close graft cases against President Asif Ali Zardari, Prime Minister Raja Pervez Ashraf told the Supreme Court Tuesday.

Ashraf said the government has decided to withdraw ex-attorney general Malik Qayyum's letter that was written to the Swiss authorities during then president Musharraf's tenure, Geo News reported.

The prime minister Tuesday appeared before the Supreme Court, which had last month given him three-weeks' time to write to Swiss authorities on reopening corruption cases against President Zardari.

The prime minister said he has directed Law Minister Farooq H. Naek to withdraw the letter written to Swiss authorities asking for closing of all the cases against the president.

The cases that had been closed by Malik Qayyum's letter can now be reopened by the Swiss authorities if they choose, the media report said.

On Aug 27, the Supreme Court had given a three-week reprieve to Ashraf by adjourning the contempt case against him till Sep 18.

The court had July 25 given Ashraf time till Aug 8 to write to Swiss authorities to reopen corruption cases against Zardari.

Accused of graft, Zardari was granted amnesty under the National Reconciliation Ordinance (NRO) in 2007 by then president Pervez Musharraf to facilitate his return home from exile, and primarily that of his wife, former prime minister Benazir Bhutto.

Zardari and Bhutto were suspected of using Swiss accounts to launder about $12 million in alleged bribes paid by companies seeking customs inspection contracts in the 1990s.

The NRO that granted immunity to politicians and bureaucrats in corruption cases was struck down by the Supreme Court as void in 2009.

The apex court in January ordered Gilani to write a letter to the Swiss authorities to reopen cases against Zardari.

Gilani was convicted April 26 of contempt of court, and was disqualified as prime minister as well as parliament member June 19.