ISLAMABAD, Pakistan — Pakistan’s highest court escalated its clash with the government on Monday by initiating contempt-of-court proceedings against Prime Minister Yousaf Raza Gilani for failing to pursue corruption charges against his boss, President Asif Ali Zardari.

The Supreme Court was clearly infuriated after the government’s lawyer said that the government had given no instructions on how to respond to the court’s demands.

Justice Nasir-ul-Mulk ordered Mr. Gilani to appear on Thursday to explain why he should not be charged with contempt, a count that could open the door to his dismissal from office.

“We are left with no option,” Justice Mulk told a courtroom packed with lawyers, journalists and politicians.