IPakistan's Supreme Court has charged the prime minister with contempt for defying its orders to reopen a corruption case against his political ally, President Asif Ali Zardari.
The development escalates a political crisis that has gripped the nuclear-armed nation
If found guilty, prime minister Yousuf Raza Gilani could be imprisoned and lose his job.
The court will now hear the case. A verdict could take several weeks or months.
Mr Gilani has refused to order the corruption investigation into Mr Zardari, saying the president has immunity from prosecution while in office.