WASHINGTON — Strong foreign demand for U.S. soybeans continued with export sales for the week ended Dec. 6 the highest since the start of the marketing year Sept. 1, according to the U.S. Department of Agriculture.

Net sales of soybeans for delivery in 2012-13 were 1,319,400 tonnes during the week, up 16% from strong sales of 1,142,700 tonnes a week earlier and up “noticeably” from the prior four-week average, the U.S.D.A. said in its weekly Export Sales Highlights. The major buyer was China, taking 1,008,800 tonnes, or 76%, of the latest week’s total sales.

The week’s sales exceeded pre-report trade expectations that ranged from 550,000 to 900,000 tonnes. The prior week’s sales also had exceeded trade expectations.

Nearby soybean futures contracts on the CME Group were trading 10@14c a bu higher at around 9:15 a.m. Central Time on the strong sales numbers, according to traders.

Total export sales commitments of soybeans for the 2012-13 marketing year through Dec. 6 were up 32% from the same period a year earlier, according to U.S.D.A. data. In comparison, wheat export sales commitments for the marketing year to date were down 9% and corn commitments were down 46% from a year earlier.