BEIJING, Jan 31 Reuters Oil prices fell on Wednesday as lacklustre economic activity in China, the world39;s biggest crude importer, weighed on sentiment, but prices were set for their first monthly gain since September as broadening Middle East conflicts raised supply concerns.

Brent crude futures for March, which expire today, fell 31 cents, or 0.4, to 82.56 a barrel by 0700 GMT. The more activelytraded April contract fell 29 cents to 82.21.

U.S. West Texas Intermediate crude futures declined 25 cents, or 0.3, to 77.57 a barrel.

Manufacturing activity in China, the world39;s secondlargest economy and oil consumer, contracted for a fourth straight month in January, an official factory survey showed on Wednesday, suggesting economic momentum was flagging at the start of 2024.

Forecasts from several analysts, including from the Organization of the Petroleum Exporting Countries OPEC, see oil demand growth in 2024 driven primarily by Chinese consumption and signs of a slowing economy there undercut those outlooks.

The Chinese manufacturing sector remains under pressure amid a weak domestic recovery and poor external demand, said Lynn Song, chief economist at ING bank, in a note.

However, both oil benchmarks are set to rise this month as the IsraelHamas war has expanded to a naval conflict in the Red Sea between the U.S. and Iranaligned Houthi militants that has disrupted oil and natural gas tanker shipping routes and added to delivery costs. Other Iranian militant…