Less than two hours after a truce between protesters and police was called, rocks and tear gas began flying again in Cairo's Tahrir Square. According to CNN, religious scholars used a "human shield" technique to separate protesters and security forces. Al Jazeera also reports the religious scholars brokered the truce, but photos showed Army soldiers standing between police and protesters. Reporter Ian Lee Tweeted an hour ago that "protesters are clearing Mohamed Mahmoud street of debris but are keeping some of the barricades." Egyptian actor Ashraf Hamdi also tweeted, "Truce occurred and now no violence taking place in mohamed mahmoud street, and process in cleaning the street." But about an hour and a half after it was called, the truce appears to have ended. Lee tweeted, "Tear gas fired again. Crowd disperses. Rocks are flying." Al Jazeera English tweeted: "AJE online producer Asad Hashim says police have just ended the cease fire near the Interior Ministry w/ tear gas barrage." And law student Sharif Hashem tweeted: "Bye bye truce. Day five will be same as ever it seems." The fighting had lasted for hours on Mohammed Mahmoud Street, The Telegraph reports, with protesters reporting police used live bullets. The United Nations has called for a probe into the police's alleged killing and abuse of protesters, Al Jazeera reports.