Calm prevailed in Kasr el-Aini street on Sunday after the building of concrete barriers by the army engineers to protect vital installations and separate between protesters and security men. Clashes now seem to be centered around the US Embassy here and Omar Mokram mosque with protesters hurling stones at security men who fired back by throwing tear gas canisters to force them to go back to Tahrir Square. Large numbers of school students, both males and females, are seen among the protesters, some wearing school uniforms, MENA correspondent said. Besides the makeshift hospital at the start of Talaat Harab street, another one was built inside the garden at the heart of Tahrir Square to treat the injured who got suffocated from tear gas inhalation.