China's factory activity shrank for the fifth straight month in September, and though the downturn eased off slightly the underlying trend pointed to persistent pressure on the economy as it navigates a bruising trade war with the United States.

Persistent weakness in the manufacturing sector backs market expectations that more policy support measures may be needed to stave off China's worst slowdown in decades.

The official Purchasing Managers' Index (PMI) was at 49.8 in September, slightly higher than 49.5 in August, data from the National Bureau of Statistics showed. The 50-point mark separates expansion from contraction on a monthly basis.