More Chinese cities saw prices of new homes fall in June compared with the previous month, official data showed Monday, as Beijing vowed to step up efforts to cool its real estate market. The cost of new apartments in 12 out of 70 Chinese cities tracked by the National Bureau of Statistics fell, compared with nine cities in May, the NBS said in a statement. New home prices increased in 44 cities in June from the previous month -- down from 50 in May -- and were unchanged in 14 others. Soaring property prices are a major source of official and consumer concern in China with apartment costs rising out of the reach of many people and threatening to spark social unrest in the country of more than 1.3 billion. The cost of new homes in 67 of the cities surveyed rose year-on-year in June -- unchanged from April and May. China has introduced a range of measures aimed at reducing prices since late 2009, such as bans on buying second homes in some cities, hiking minimum downpayments and trialling property taxes in Shanghai and Chongqing. But officials are treading carefully as the real estate sector is a major driver of economic growth and land sales to developers are an important source of revenue for cash-strapped local governments. The government last week pledged to extend limits on new home purchases to smaller cities, adding it would tighten existing property restrictions in areas that have seen excessive price rises to push them \"back to reasonable levels\". To tame soaring prices and other consumer costs the central bank has also raised interest rates five times since October and increased the amount of money banks must keep in reserve numerous times.