A youth was critically injured as protesters clashed with security forces in old city area after the congregational Friday prayers, police said.Protesting youth pelted stones at security personnel in Nowhatta area after prayers at the Jamia Masjid and security forces used tear smoke shells and pellets to disperse them.An unidentified youth was seriously injured during the clashes and taken to SMHS hospital, where doctors said he had sustained critical pellet injuries in the abdomen area.