Pakistan's Supreme Court adjourned a contempt hearing for its prime minister on Thursday, leaving a brewing political crisis over corruption cases, presidential immunity and the possible fate of the government unresolved.

Yusuf Raza Gilani was in court to explain why he should not be charged with contempt for failing to re-open old corruption cases against his boss, President Asif Ali Zardari. The government maintains Zardari enjoys presidential immunity.

It is my conviction that he (Zardari) has complete immunity inside and outside the country, Gilani told the court. In the constitution, there is complete immunity for the president. There is no doubt about that.

The immediate battle is about Gilani, but the larger political crisis is about Zardari and the fate of his government, the longest-running civilian administration in Pakistan's coup-marred history.

If Gilani is charged with contempt of court for failing to follow court orders, he could be disqualified from office and forced to resign.

That would further increase the pressure on the unpopular civilian government and the risk of instability in the nuclear-armed ally in America's war on militancy.

Thursday's adjournment did nothing to settle the issue, and was mainly to allow Gilani to explain his position.

After the hearing, a confident-looking Gilani appeared outside the court smiling and waving. Television stations reported that the court agreed that he would not have to appear again personally before the court when it reconvenes on February 1.

Gilani's legal troubles are the latest blow for the civilian administration which also faces pressure from the military over a mysterious memo seeking U.S. help to avert an alleged coup last year.

RE-OPEN CASES

Ahead of the court hearing, police blocked off parts of the capital city to impose tighter security in the South Asian country facing homegrown Taliban militants blamed for many of the suicide bombings that have kept foreign investors away.

Hundreds of policemen were stationed outside the Supreme Court as every car was checked. Gilani's security men, in dark suits, combed the premises.

While Gilani is the one facing a contempt hearing, most observers say the court's real target is Zardari.

During the 1990s, Zardari had multiple cases of corruption and even murder lodged against him, all of which he says are false and politically motivated.

An amnesty deal that protected him from prosecution was nullified in 2009 and the court has been pushing for the government to re-open and investigate the corruption cases against Zardari.

The government refuses to do so, saying Zardari enjoys immunity as the head of state.

In an exchange with the judges, Aitzaz Ahsan, the prime minister's lawyer, said the government could not write a letter to Swiss authorities to re-open the corruption cases.

The letter shall be written when ... Asif Ali Zardari is no longer the president, Ahsan told the bench.

The judge said so you're saying you won't write it?

Ahsan responded: I don't have the capacity to write the letter because the president has immunity.

Gilani won a unanimous vote of confidence in parliament when he became prime minister nearly four years ago, and has been known as a peacemaker even among the ruling Pakistan People's Party's most bitter enemies. Unlike Zardari, he was seen as having smooth ties with the military before the latest turmoil.

But his diplomatic skills may not be enough to fend off both the Supreme Court and Pakistan's generals, who have ruled the country for more than half of its 64 years history through coups, and from behind the scenes.

The fact is that it's not just the anger of the judges against the PM, it's the anger of the army against the PM as well, said Ayesha Siddiqa, a prominent defence analyst.

(Additional reporting by Serena Chaudhry in ISLAMABAD, Sahar Ahmed and Faisal Aziz in KARACHI; Writing by Chris Allbritton; Editing by Sanjeev Miglani)