Two Egyptian police officers were shot and killed while guarding a Coptic Christian church on Tuesday. The men died instantly after masked gunman fired on them, a local security source and a witness told Reuters. Wednesday marks Coptic Christmas this year, which usually involves tightened security at Egyptian churches. Coptic Christians, who make up about 10 percent of Egypt’s population, have lived peacefully with the nation’s Sunni Muslim majority for years. However, following the ousting of Egyptian President Mohamed Morsi, many Christian churches and properties have been destroyed.