HONG KONG - An official survey released Saturday said that China’s factory activity expanded in September at the fastest pace in five years, as the country’s vital manufacturing sector stepped up production to meet strong demand.

The official manufacturing purchasing managers’ index rose to 52.4 in September, up from 51.7 in the previous month and the highest level since April 2012.

The report by the Federation of Logistics & Purchasing said production, new export orders and overall new orders grew at a faster pace for the month.

“The manufacturing sector continues to maintain a steady development trend and the pace is accelerating,” said Zhao Qinghe, senior statistician at the National Bureau of Statistics, which released the data. Zhao noted that the report found both domestic and global demand have improved.

However, in a separate report, the private Caixin/Markit manufacturing PMI slipped to 51.0 from 51.6, as factories reported that production and new orders expanded at slower rates last month.

Both indexes are based on a 100-point scale with 50 dividing expansion from contraction. But the federation’s report is focused more on large, state-owned enterprises while the Caixin survey is weighted to smaller, private companies.

Another official index covering non-manufacturing activity rebounded after two months of contraction, rising to 55.4 last month from 53.4 in August. That indicates momentum is picking up again in China’s service sector.

The reports come ahead of the ruling Communist Party’s twice-a-decade congress set for next month, where top leaders will be reshuffled and authorities will outline economic policies.

Earlier this month, rating agency Standard & Poor’s downgraded China’s credit rating on government borrowing, citing rising debt levels that raise financial risks and could drag on economic growth.