China's value-added industrial output expanded 6.9 percent year on year in August, down from the 9-percent growth in July, the National Bureau of Statistics said on Saturday.

On a monthly basis, the industrial output in August expanded by a fractional 0.2 percent from July, the NBS said in a statement. In the first eight months, total value-added industrial output grew 8.5 percent from the same period last year.

August marked the second monthly retreat seen in the growth rate, after industrial output grew 9.2 percent in June, its fastest pace since January.

"An obvious drop was seen in the industrial output growth for August," said Jiang Yuan, a senior analyst with the NBS, citing reasons ranging from weak external demand to tempered growth of auto and cell phone production.