Opposition parties opposed to the dismissal of Pakistan's chief justice, Iftikhar Chaudhry, were calling for a nationwide strike on Monday to protest violence in Karachi that left 42 people dead over the weekend. On Monday, gunmen killed a senior official of Pakistan's highest court at his home in Islamabad before dawn, The Associated Press cited police as saying. The person has been identified as Syed Hamid Raza, an additional registrar at the supreme court, and the motive was not known, AP quoted a local police chief as saying. A hearing into Chaudhry's case at the Supreme Court was halted Monday, after one of 14 judges on the bench refused to hear the case. "This bench will be reconstituted, maybe tomorrow," Tariq Mehmood, a lawyer for Chaudhry, told Reuters. All of Pakistan's civil and higher courts remain closed across Pakistan because of an ongoing boycott by the country's lawyers. Security forces in Karachi had stepped up patrols, and there was no violence on Monday, despite high tensions, Reuters cited police chief Azhar Farooqi as saying. On Sunday Pakistan's government gave its paramilitary forces authority to shoot on sight in an effort to quell political clashes in Karachi. Chaudhry had been scheduled to address a bar association meeting there on Saturday but was forced to turn back to Islamabad because of the upheaval.