China's manufacturing activity expanded at a faster pace in August than it did in July, according to a survey of purchasing managers released on Saturday.

The Purchasing Managers' Index rose to 54, from 53.3 in July, the China Federation of Logistics and Purchasing and the National Bureau of Statistics said in a statement.

The acceleration, the first in four months, comes as China tries to cool the export-driven economy after the fastest expansion in more than 12 years, Bloomberg News reported. Money flooding in from record trade surpluses threatens to fuel asset bubbles, spiraling inflation and overcapacity in manufacturing.

"The cause may be seasonal because factories normally reduce production in June and July and resume full capacity after the summer," said Zhu Baoliang, chief economist at the State Information Center in Beijing.

Saturday's release was a surprise because the data are usually distributed on the first working day of each month.

The world's fourth-biggest economy grew 11.9 percent from a year earlier in the second quarter. The central bank raised interest rates on Aug. 22 for the fourth time since March. It also curbed export-tax rebates to cool growth in overseas sales.

The economy won't keep heating up, the government statement quoted analyst Zhang Liqun as saying.

The purchasing price index increased to 63 from 58.9, the biggest gain of the August measures. That reflects a "prolonged shortage" of metal raw materials and increased food costs, according to Zhu.

The output index rose to 57.1 in August from 55.7 in July, while the index of new orders climbed to 56.3 from 56, the government said. The index of export orders increased to 55.2, the highest level in three months, from 53.5.