Karachi, Aug 04: The influx of internally displaced persons (IDPs) from volatile North Waziristan into Sindh worries nationalist parties in the province. Sindh Bachao Committee (Save Sindh Committee) in association with a dozen of other Sindhi nationalist parties recently observed a complete shutter down strike across Sindh, including Karachi. Their major concern is the possible invasion of Tehreek-e-Taliban Pakistan militants in the region since after Pakistan Army launched 'Zarh-e-Azb' operation against terrorist groups based in North Waziristan. There are fears about a rise in sectarian violence and other terrorist activities in Sindh. The growth of fundamentalist groups, many with links to armed factions, has been alarmingly rapid in Sindh and has brought violence in its wake.