HONG KONG — Chinese factory activity and retail sales picked up a notch in April, according to data released on Monday. But expansion remained underwhelming, analysts said, reinforcing the conclusion that the once surging Chinese economy is making a long-term transition toward slower growth.

Industrial output, the National Bureau of Statistics said, expanded 9.3 percent from April of last year, compared with the 8.9 percent reading in March, while retail sales grew 12.8 percent, compared with 12.6 percent in March. Analysts cautioned that the improvements did not represent a substantive pickup in growth and that the momentum in the Chinese economy remained muted.

Fixed-asset investment, an important engine of economic growth, grew 20.6 percent in the first four months of the year, but the figure was lower than analysts had forecast.

“This is not the start of a rally. It is a sputtering whimper as momentum continues to fade,” Xianfang Ren and Alistair Thornton, economists at IHS Global Insight in Beijing, said in a research note.

Although they emphasized that “fading momentum is not the same as collapsing growth” and that the government would probably be able to engineer full-year gross domestic product growth of more than 7.5 percent this year, they added, “we feel the risks remain firmly on the downside.”

The data suggest that the Chinese economy is stabilizing, Helen Qiao, chief economist for Greater China at Morgan Stanley, said at a news briefing. But “the question remains whether the growth recovery is sustainable or not” and how long the current softness will last, she said.

The figures released on Monday were the latest in a series of disappointing indicators from the Chinese economy in recent weeks. Data released last month showed that the economy had expanded 7.7 percent in the January-to-March quarter, compared with the same period last year. Analysts expected 8 percent. Two surveys of purchasing managers in the manufacturing sector showed that April activity was disappointing, thanks in large part to weakness in new orders for exports. And last week, the Canton Fair, China’s biggest export event, announced that export orders placed at the spring session had fallen 1.4 percent from a year ago.

In part, the weakness stems from the euro zone’s festering debt crisis and austerity measures, which have eroded the ability and desire of European customers to spend, hurting exports from China. Rising wages in China and a gradually appreciating currency have also started to erode the country’s international competitiveness.

China is putting its own brakes on the economy with reforms that are likely to ensure that the double-digit expansion rates of much of the last three decades are over. Aware that the economy cannot continue to grow on the strength of exports and heavy industry alone, Beijing has begun to steer China toward growth focused on domestic demand and urbanization. While that should help raise living standards and productivity, it will also mean slower growth, analysts say.

At the same time, Beijing is trying to keep a lid on risk like the expansion in local government debt, which some analysts worry could turn sour, and lending activity outside the regulated banking system. Such so-called shadow banking has been growing rapidly in the last few years and has become an important source of financing for companies and local governments. But shadow banking is relatively opaque and loosely regulated, and it carries greater credit risk, analysts warn.

Moody’s underlined the concerns about shadow banking in a report released on Monday. The credit ratings agency welcomed recent regulatory steps to tighten controls and restrict the growth of shadow banking, but, it said, “The opacity associated with shadow banking products and the threat of loss and contagion outweigh their potential benefits in terms of diverting riskier borrowers from the formal banking system.”