China's investment in factories and other urban fixed assets soared by a stunning 31.3 percent in the first six months of the year, the government said Thursday, highlighting official worries that a building boom could ignite a financial crisis.

The growth rate was even faster than last year's pace of 27.1 percent in the same period, the National Statistics Bureau said.

Chinese leaders have warned that a surge in lending for building projects could ignite inflation, while banks could face financial problems if developers of unneeded assets default on their loans.

Beijing has tried to block new construction by tightening lending rules and banning some types of construction. But officials are often reluctant to enforce limits that might hurt local companies.

The government said Tuesday that overall economic growth surged to 11.3 percent in the second quarter, driven by the building boom.

Economists expect China to respond by raising interest rates again and possibly allowing a rise in the value of its currency, the yuan, in an effort to cool off growth.