Pakistan's top court has initiated contempt proceedings against the prime minister for failing to carry out the court's order to open a corruption probe into the president.
The Supreme Court ruling against Prime Minister Yousuf Raza Gilani means he could be prosecuted, leading to his dismissal.
The court ordered Mr Gilani to appear before the court on Thursday to explain why he has not complied with the order.
Judges are ordering the government to open a corruption probe into President Asif Ali Zardari dating back to the 1990s.
The government has refused, saying Mr Zardari has immunity.