CAIRO - Police have detained a score of men who tried to break into el-Mazraa Prison on Friday morning to free hundreds of inmates, including ex-Interior Minister Habib el-Adli, who is awaiting trial next month, security sources said. The unidentified men tried to storm into the prison building on the outskirts of Cairo to release their imprisoned friends and family members including el-Adli, who has been charged with committing capital crimes, the sources added. The break-in attempt is the latest in a string of embarrassing security lapses in Egypt, raising questions about the country's ability to ensure its own security after the January 25 revolution, which toppled Mubarak. The entire prison staff as well as riot police fired warning shots in the air to disperse the crowd and prevent the convicts from escaping, according to the sources. The police arrested 20 suspects, who said that they were trying to release their relatives and friends, who should only be set free after serving half of their prison terms in accordance with a decree issued by ex-Interior Minister Major-General Mahmoud Wagdi. The attack on el-Mazraa (The Farm) Prison, in Tora, south of Cairo, came just one hour before the weekly Friday noon prayers. Authorities said the attackers tried to prise open the main gate to help the convicts, who were gathering in the main courtyard, to escape. However, no-one on the inside appears to have been actively involved in organising the failed breakout, they stressed. The attack triggered an immediate backlash in Cairo against top security officials, while a special committee has been formed to investigate the incident. The committee has ordered that the number of police checkpoints be increased on the road leading to el-Mazraa Prison. Official figures have shown that one-quarter of the nation's prisoners have managed to escape since January 28. Some allege that the prison breaks have been engineered by the embattled el-Adli, who is trying to cling to power by creating anarchy. A few days after the revolt began on Jan. 25, police vanished from the streets and the military took over ��" a transition that was followed immediately by the eruption of looting, arson and lawlessness on the streets of the capital, Cairo.