| Gilani, right, was called to explain his refusal to ask Switzerland to re-open graft cases against Zardari, left [EPA]
Pakistan's prime minister has appealed against a supreme court summons to appear for a hearing over his refusal to pursue corruption cases against the country's president.
A lawyer for Yousuf Raza Gilani filed the appeal on the the prime minister's behalf on Wednesday, saying he was basing the move on precedents set by top courts in Australia, France, India, the UK and the US.
"I have filed an appeal today. I have quoted more than 50 national and international cases and given specific reasons against the supreme court order," Aitzaz Ahsan said.
A court official confirmed that the appeal had been received.
If convicted of contempt, the prime minister could be jailed for up to six months and disqualified from public office.
Grounds to proceed
The court ordered Gilani last week to appear before judges on February 13 to be charged with contempt of court.
Judge Nasir-ul-Mulk told the supreme court on February 2 that there were grounds to proceed against Gilani, despite the government's insistence that Pakistani President Asif Ali Zardari has immunity from prosecution while he is head of state.
"After the preliminary hearing, we are satisfied that prima facie there is a case for further proceeding into the matter."
"Adjourned for February 13, for framing charges. Prime minister is required to remain present in the court," Mulk said then, reading out the order in English.
No comments on judiciary
In his response to the ruling, Gilani said he would "refrain from making comments" on the judiciary. He said he firmly believed that "everybody should follow the constitution".
Gilani went before the court on January 19 to explain his refusal to ask Switzerland to re-open graft cases against Zardari on the grounds of the head of state's immunity.
Sheik Usmani, retired justice of the supreme court, said that a conviction would not be inconceivable, even for a person with "the stature of the prime minister".
A defendant has the right to appeal in a contempt case in Pakistan even before a trial begins, but Gilani's lawyer expressed concern about the possible civil turmoil that such a prominent case might produce.
Government supporters say the court is trying to remove Zardari because of enmity between Zardari and the chief justice.
The court has also ordered an inquiry into a secret memo scandal that is also threatening Zardari.
The memo was allegedly sent to Washington DC by the government last year asking for help in stopping a supposed military coup.
The government has denied the allegations, and the case appeared to lose steam last week when the main witness refused to come to Pakistan to testify.
It is only the second time that Pakistan's highest court has pursued contempt proceedings against a sitting prime minister, plunging the weak government deeper into a crisis that could force early elections within months.