SINGAPORE - Chicago soybeans firmed on Friday, but the market was on track for its first monthly decline as lower-than-expected Chinese buying sapped investor sentiment.

Corn prices firmed but were headed for a weekly loss as the near-complete U.S. harvest and favourable South American planting conditions weighed on the market, while wheat rose and was set for weekly gains.

"China's soybean purchases have been fairly muted so far,” said one oilseed trader. "We have yet to see the large volumes that have been talked about."

The most-active soybean contract on the Chicago Board of Trade (CBOT) added 0.5% to $11.12-3/4 a bushel, as of 0324 GMT, with prices down 0.2% for the week.

Corn added 0.1% to $4.29 a bushel and wheat was up 0.4% at $5.37-1/2 a bushel. While corn has lost 0.6% this week, wheat is up 0.6%.

China has begun modest purchases of U.S. farm products after the leaders of both countries met last week, but traders still await significant soybean buys after the White House said Beijing pledged to buy 12 million tons by year-end.

Caution over soybean demand was reinforced by a lack of any details from a soybean procurement signing ceremony on Thursday held in Shanghai.

China, by far the world's largest soybean buyer, imported 9.48 million tonnes of the oilseed in October, a record for the month but down 26.3% from 12.87 million tonnes in September, figures from the General Administration of Customs of China showed.

China has stepped up soybean imports this year, taking record volumes for several months from South America to build inventories ahead of U.S. marketing season amid the trade war.

For wheat, China has booked just two cargoes of U.S. wheat, Reuters reported, suggesting a smaller volume than speculation of several hundred thousand tons.

The wheat market is likely to face headwinds from accelerating exports from Russia, and competition from southern hemisphere exporters Argentina and Australia that are starting their harvests.

Traders are also beginning to focus on the USDA's November supply and demand report, which the department plans to publish next week after skipping its October report due to the ongoing U.S. government shutdown.