Authorities in the Sichuan city of Shifang said yesterday they would scrap plans to build a heavy-metal processing plant after violent clashes between tens of thousands of anti-pollution protesters and riot police escalated for a third day. Late last night, thousands of residents gathered again outside the city government headquarters demanding the release of an unspecified number of people detained during the three-day demonstration, mostly students, according to witnesses' accounts and photos posted last night on Sina Weibo. They chanted slogans such as 'release the kids'. Anti-riot police tried to disperse the crowds. In a dramatic turn of events, Shifang officials made a rare compromise amid mounting public pressure, vowing the molybdenum-copper alloy plant would be scrapped. 'Given the fact that some people are worried about the environmental impact and health hazards of the project and reacted fiercely, [we] have decided to stop construction on the plant and it will never be built in Shifang,' the city's Communist Party chief, Li Chengjin, said in a statement yesterday. Witnesses in Shifang, which was devastated by the Sichuan earthquake in 2008, said more protesters showed up near the city centre yesterday than on the two previous days of demonstrations. People were defying a heavy security presence and an unusually harsh warning issued by the city government earlier in the day that protesters would be 'severely punished' if they sought to continue the 'illegal' protests. There were many reports of violence against peaceful demonstrators, including teenage students, with photos posted online showing bloodied protesters and police wielding batons and firing tear gas. 'Thousands of people took to the streets today, even more than yesterday, simply because we don't believe what the government has promised,' said a woman who works at a teahouse close to the city administration's headquarters. She said police fired tear gas and stun grenades about every half an hour and many people were injured as officers used force to disperse crowds gathered outside government buildings and on main streets. Another witness, who works at a mobile phone store in the city centre, said about 8,000 police were stationed along major roads and at hospitals. However, the local government denied there was mass bloodshed or a large number of casualties, saying only a few residents, cadres and police officers were injured because police had 'exercised great restraint' in their efforts to disperse the protesters. In a statement posted on the official website of the city government's press office yesterday afternoon, the authorities denied a widely circulated online rumour that one protester had been beaten to death. Li admitted that the government had failed to give the public adequate information about the controversial alloy plant or heed public concerns, leading to one of the largest protests on the mainland in years. Protests in Shifang, a county-level city in Deyang , began on Sunday night, just two days after construction of the molybdenum-copper alloy plant was allowed to start. The 10.4 billion yuan (HK$12.77 billion) Sichuan Hongda plant, reportedly close to Shifang's freshwater source, would have been the most expensive single project built in Deyang, the city government's official website said. Calls to Sichuan Hongda, based in Chengdu , went unanswered yesterday. The plant, listed as a key project in the reconstruction of the quake-hit region, was approved by the Ministry of Environmental Protection in March.