By Agence France-Presse Police in central China said Sunday they arrested nearly 50 people after a violent protest sparked by dissatisfaction with the local school system. More than 600 protesters gathered outside a police station in Leiyang city in Hunan province around midnight Saturday after security personnel stopped a protest earlier in the day, police said in a statement on their website. Education is a sensitive subject in modern-day China (AFP Photo/Chandan KHANNA/MANILA BULLETIN) They said they arrested 46 people who "attacked" the station, throwing bottles and bricks at local officials attempting to address the crowd. Many cars had been destroyed, the statement added. Apparent videos of the protests on Twitter showed an angry crowd violently clashing with police in riot gear. AFP could not independently confirm the video. Trouble began after parents of some middle school students were told they would have to move their children into dormitories at a local private school, resulting in a dramatic increase in tuition fees, according to posts on Chinese social media. Additionally, commenters complained that unsafe levels of formaldehyde had been detected in some middle schools' newly renovated dormitories. Posts about the incident had been removed from Chinese social media by Sunday afternoon but were preserved by the anti-censorship website Free Weibo. In a statement on its website, the local education department said it would test the dorms' formaldehyde levels immediately. Violent protests are not uncommon in China, where citizens have limited channels for addressing their frustrations with government. Problems affecting children's health and education are particularly sensitive subjects in the country, where government policy for decades limited parents to only one child.