BEIJING, Sept. 14 (Xinhua) -- China's economy maintains steady growth amid domestic and external challenges as the country pushes structural reform and fosters new growth drivers.

The country registered sound growth in industrial output and retail sales, though fixed-asset investment increase continued to slow, data from the National Bureau of Statistics (NBS) showed Friday.

Despite fluctuation of some indicators, NBS spokesperson Mao Shengyong said the economy has been generally stable with improving momentum for growth.

Industrial output rose 6.1 percent in August from one year earlier, a notch higher than July's 6-percent rise.

The output of 336 of 596 key industrial products monitored by the government, including steel, coal, crude oil, and integrated circuits, climbed, but production of autos, ethylene, and computers fell.

Retail sales posted a better-than-expected growth of 9 percent last month, accelerating from 8.8 percent in July. Analysts had forecast an increase of 8.8 percent for August.

Fixed-asset investment (FAI) growth further slowed to 5.3 percent for January-August, weighed down again by weakening infrastructure investment.

The growth of infrastructure investment continued to slow, albeit more modestly. Infrastructure investment increased 4.2 percent in the first eight months, down from 5.7 percent for January-July.

To boost infrastructure investment, the country has accelerated approval of railway and grid projects over the past few months.

Railway investment in the January-August period reached 461.2 billion yuan (67.4 billion U.S. dollars), or 63 percent of the total railway investment planned for the whole year, according to the China Railway Corporation. It was up from 56.8 percent for the same period last year.

Mao expected the FAI growth to stabilize in the coming months as the government's policies to boost infrastructure investment will gradually come through, while property investment and manufacturing investment maintain stable increases.

He said the government will increase investment in sectors of infrastructure and public services in the country's comparatively less-developed central and western regions.

Besides boosting investment, the country's central bank has been injecting funds into the market through open market operations to lower financing costs and urged financial institutions to enhance support for small and micro businesses.

As the country continued to restructure the economy and foster new growth drivers, the high-tech sector, strategic emerging industries, equipment manufacturing and services posted fast expansion.

Looking ahead, Mao warned about risks from a more complicated external environment and long-standing issues caused by domestic structural imbalance.

The country's GDP expanded 6.8 percent in the first half of the year, above the government's annual target of around 6.5 percent. The growth has remained between 6.7 percent and 6.9 percent for 12 consecutive quarters, highlighting its economic resilience.

The sound economic fundamentals have remained unchanged, providing a solid foundation for the economy to weather challenges, said Wang Jun, chief economist at the Central China Securities.