Minya (Upper Egypt) - Twenty eight people have been killed in Egypt after unidentified gunmen opened fire on a bus carrying Coptic Christians, according to state-run media. The passengers were traveling Friday to a monastery, St. Samuel the Confessor, near the central city of Minya when they came under attack, Health Ministry spokesman Khaled Mugahed told TV al-Masriya. He said that 25 others were also injured as the gunmen fired from two cars on a desert road around 100 km (62 miles) west of Minya. Fifty ambulances are now at the scene. There were men, women and children among the dead and injured, Mugahed said, some of whom are now in critical condition. It was not immediately clear who was responsible for the shooting. Coptic Christians have faced persecution and discrimination in Egypt, which has spiked since the toppling of Hosni Mubarak's regime in 2011. Dozens have been killed in sectarian violence. Coptic Christians make up about 10% of Egypt's population of 91 million. They base their theology on the teachings of the apostle Mark, who introduced Christianity to Egypt.