ISLAMABAD, Jan 11: In a major blow to the Nawaz Sharif government, Pakistan's Supreme Court today stayed execution of all death sentences, awarded by the controversial military courts to provide `speedy justice', till the disposal of a number of petitions challenging the validity of these courts.A seven-member bench of the court, led by Chief Justice Ajmal Mian, passed a brief order staying the execution of the sentences awarded by these courts established in Karachi after the imposition of governor's rule in Sindh province in October last.The court gave the order while hearing five petitions, including one from Karachi-based Muttahida Quami Movement (MQM), and issued notices to respondents Attorney General of Pakistan and Advocate General of Sindh province. Of the two persons executed, one was an MQM activist. The party alleges the courts have been set up to target it and not criminal elements.Feuding factions of the MQM have been blamed for the relentless violence that has terrorized southernKarachi and left more than 1,000 people dead in the past one year.The court ordered that the hearing of all the petitions challenging the military courts would start from February one and ``till those hearing the respondents shall not execute death sentences already awarded or which may be awarded hereafter''.The order came after Attorney General Choudhury Muhammad Farooq read out a letter from Sharif which justified military courts and criticized the procedure of normal courts. The letter was actually written by Sharif to the AG himself drawing attention towards growing violence in Pakistan and mentioning the attempt on the premier's life a week ago.Sharif also referred to the murder of Iranian diplomat Sadiq Ganji, a case which is pending before the high court for the past six years, and said, ``In abnormal times, normal legal processes are often perceived as being hazardous and inadequate by judges themselves for no fault of their own.'' Sharif also praised the working of the military courts. Themilitary courts operate at a military base on the outskirts of Karachi. The army appoints both the prosecution and defence lawyers and the judge is also an army official.There courts have been mandated to give a quick hearing to cases and decide on the trial within a week. While law enforcers say that this is the only way to have known criminal and political terrorists punished for their crimes, human rights organisations and lawyers have protested against this.