ISLAMABAD (AFP) -- Unidentified gunmen killed a senior Supreme Court official in Islamabad early Monday after a weekend of deadly violence over the suspension of Pakistan's top judge, police said.

Syed Hamid Raza was shot dead hours before the court was due to start a hearing into the legality of charges against Chief Justice Iftikhar Muhammad Chaudhry.

"Unknown gunmen broke into the house of Supreme Court additional registrar Raza and shot him dead," Islamabad police officer Mohammad Aslam told AFP.

Police were still investigating the motive for the killing, he said.

The shooting follows a weekend of bloodshed in the southern city of Karachi, in which nearly 40 people were killed, after pro-government activists stopped a rally by the sacked judge.

President Pervez Musharraf, a key U.S. ally, sacked Chaudhry on March 9, sparking a wave of protests.