US corn and soyabean futures fell on Wednesday on uncertainty surrounding US-China trade talks, along with pressure from the expanding Midwest harvest, analysts said.

Wheat futures bucked the weak trend, climbing on technical buying and news that Egypt, a top global importer, bought 405,000 tonnes of wheat in its latest international tender.

As of 1:01 p.m. CDT (1801 GMT), Chicago Board of Trade December corn was down 2 cents at $3.91-1/4 per bushel and November soyabeans were down 5 cents at $9.29 a bushel. CBOT December wheat was up 4-3/4 cents at $5.11-3/4 a bushel. Traders continue to watch for fresh Chinese demand for US agricultural products. US President Donald Trump said on Friday that China had agreed to purchase $40 billion to $50 billion worth of US agricultural goods in a first phase of an agreement to end a 15-month trade war.

But China would make the purchases only if Trump rolls back levies put in place since the trade war began, Bloomberg reported on Tuesday, citing people familiar with the matter.

Meanwhile, the US corn and soya harvest is progressing under clearing skies in much of the Midwest this week, even as crop maturity has lagged following widespread planting delays this past spring.

The US Department of Agriculture late on Tuesday said that 22% of the corn crop had been harvested, behind market expectations, and 26% of the soyabean crop, slightly ahead of market forecasts.

Corn futures shrugged off support from the USDA's confirmation that private exporters sold 228,600 tonnes of US corn to Mexico.

CBOT wheat futures rose, supported by news that Egypt bought 405,000 tonnes of Russian, French and Ukrainian wheat, at higher prices than what it bought at its last international tender on Oct. 8.