Chinese shares have fallen to their lowest point in a year after plans to tighten up on property price inflation worried investors.
Chinese Premier Wen Jiabao was quoted by the official Xinhua news agency as saying the government would curb excessive rises in property prices.
The Shanghai Composite index dropped by 5.07% to close at 2,559.93 points.
Dealers were also worried about falls in other world markets, caused by continuing fears about the eurozone.
Property price inflation rose 12.8% in the year to April to a five-year high in China.
The authorities have announced a series of measures designed to take the heat out of the market over the past month, including increasing the size of the deposit needed to buy a second property and introducing new restrictions on loans for those buying a third property.
State media reported on Monday that China's National Development and Reform Commission was now drafting tighter rules for the property market.
The government has already introduced restrictions on bank lending, also designed to cool economic growth.