Pakistani Prime Minister Yousuf Raza Gilani was convicted on Thursday of committing a contempt of court in a case that could see him thrown out of office and jailed.

Pakistani Prime Minister Yousuf Raza Gilani was convicted on Thursday of committing a contempt of court in a case that could see him thrown out of office and jailed.

The Supreme Court ruled that Gilani was guilty of contempt for refusing to obey an order to write to the authorities in Switzerland to ask them to re-open corruption cases against President Asif Ali Zardari.

Gilani was sentenced to be detained in the court until the hearing adjourned, the state broadcaster reported, and shortly afterwards emerged smiling and waving to supporters.

"For reasons to be recorded later, the prime minister is found guilty of contempt for wilfully flouting the direction of the Supreme Court," said Justice Nasir-ul-Mulk while reading the verdict.

The prime minister had faced a maximum sentence of six months in jail in the case, but was subjected only to a symbolic detention until "the rising of the court".

The court had ordered Zardari's case, and several other ones, reopened after it struck down the National Reconciliation Ordinance (NRO), a controversial 2007 amnesty law, as being unconstitional.

Gilani says that reopening a case against a sitting president would itself be unconstitutional, as the holder of the post enjoys legal immunity while in office.

The contempt case, in court since January, has caused political instability and could force the holding of early elections if Gilani is finally disqualified from parliament and lawmakers cannot agree on a replacement.