About 135 Muslim extremists who spent more than a decade in Egyptian prisons have been released after signing statements renouncing violence, police officials said Monday. Egypt began releasing members of al-Jihad, which was formerly headed by al-Qaida's No. 2 Ayman Al-Zawahri, two weeks ago after some of their leaders agreed to renounce violence against the Egyptian state, officials said on condition of anonymity because they were not authorized to talk to the media. Al-Gamaa al-Islamiyya, which in Arabic means Islamic Group, and to a lesser extent al-Jihad, which means holy war, were responsible for a violent campaign against the Egyptian regime in the 1990s. Neither has been involved in attacks in Egypt since. Both groups were accused of participating in the 1981 assassination of President Anwar al-Sadat. Al-Zawahri was jailed for his involvement in the assassination but was released in 1984. After his release, he left Egypt and helped form al-Qaida with Osama bin Laden in the late 1990s. Al-Gamaa first proposed a unilateral cease-fire in 1997 that went into effect in March 1999. Most of its leaders, who spent 25 years in prison, as well as hundreds of its members, have since been freed from prison. Al-Jihad has long opposed the concept of reconsidering its radical views. But a few months ago, a top ideologue for al-Jihad and other militant groups, Sayed Imam Abdul-Aziz el-Sherif, 57, led a review of the group's ideology and concluded that the group should unequivocally renounce violence. El-Sherif left Egypt in 1986 to go to Afghanistan. He later wound up in Yemen where he was arrested in 2001 and handed over to Egypt in 2004. He is serving a life sentence and was not one of the militants released by authorities. Hundreds if not thousands of militants are still believed to be in prison from both militant groups as well as other smaller networks. Egypt has never disclosed an official figure of militants or political inmates in its prisons. Controversial emergency laws imposed since Sadat's assassination give security forces broad powers - including great leeway in making arrests and detaining people indefinitely.