Police reportedly used tear gas to disperse hundreds of people in a central Iranian city on the seventh day of protests to demand government action over drought. Videos on social media appeared to show police and protesters clashing in the dry bed of the Zayandehrud River. The video corresponded to known features of the area, though original posters of the material could not immediately be reached. Other videos showed similar unrest in the nearby streets of Isfahan. Iran's semi-official Fars news agency said a heavy force brought the gathering of some 500 people in Isfahan to an end. A separate report carried by Tasnim agency said unknown perpetrators had damaged a pipeline that transfer waters from Isfahan to other provinces last night. Wells, aqueducts and rivers have been drying up in recent months, including the Zayadneh Rood river that runs from the Zagros Mountains in Chahar-Mahal Bakhtiari province to south of Isfahan city. Farmers reportedly ended a weeks-long protest in the area on Thursday, after authorities promised to compensate them for losses suffered in drought-stricken areas of central Iran. Drought has been a problem in Iran for about 30 years, but it has worsened over the past decade, according to the UN's Food and Agriculture Organisation. The Iran Meteorological Organisation says that an estimated 97 per cent of the country now faces some level of drought. The farming area around Isfahan was once well supplied by the Zayandehrud river, but nearby factories have increasingly drawn on it over the years. The river once flowed under historic bridges in Isfahan’s city centre, but now there is a barren strip of dirt. In 2012, farmers clashed with police in a town in Isfahan province, breaking a water pipe that diverted some 50 million cubic meters of water a year to a neighbouring province. Similar protests have continued sporadically since then.