(Updates with closing prices, adds details)
CHICAGO, Sept 8 (Reuters) - U.S. corn and wheat futures firmed slightly on Friday, supported by a round of end-of-week bargain buying after posting sharp declines on Thursday, traders said.
Soybeans weakened on technical pressure after the market threatened, but failed to break through a four-week high hit on Thursday. Strong export demand limited the declines.
U.S. futures also drew broad support from a falling dollar as the euro climbed to a 2-1/2-year high against the U.S. currency.
Chicago Board of Trade December corn futures were 1-1/2 cents higher at $3.56-3/4 a bushel.
"Corn prices are a little higher, trying to rebound after a late selloff dented the mood on Thursday," Farm Futures analyst Bryce Knorr said in a note to clients.
Gains in corn were limited by expectations of a bumper U.S. harvest. The government will update its crop production forecast in a monthly report on Tuesday.
CBOT December wheat was 1/2 cent higher at $4.37-3/4 a bushel.
CBOT November soybeans ended down 6-3/4 cents at $9.62 a bushel.
The U.S. Agriculture Department said on Friday morning that private exporters reported the sale of 264,000 tonnes of soybeans to China for delivery during the 2017/18 marketing year, the biggest flash sale in 2-1/2 weeks.
Weekly export sales of soybeans totalled 1.16 million tonnes, the USDA said, just above market forecasts that ranged from 500,000 to 1.10 million tonnes.
China, the world's largest soybean buyer, imported 8.45 million tonnes of soybeans in August, a record for the month, figures from the General Administration of Customs of China showed.
The news underlined brisk recent demand from China that has offset supply pressure after a record Brazilian harvest this year.
"Soybeans are likely to get even firmer as China's demand is surprising," said Ole Houe, an analyst with brokerage IKON Commodities in Sydney. "They are having a solid pace of imports, it is not just beans, even feed grains."
Despite the strong demand, soybeans failed to break through the four-week high hit on Thursday.
For the week, soybean futures rose 1.3 percent, corn futures were up 0.4 percent and wheat futures were down 0.2 percent.
Soybeans were on track for their third straight week of gains, which would be the longest streak since a four-week stretch of higher closes that ended in late October 2016.
(Additional reporting by Naveen Thukral in Singpore and Gus Trompiz in Paris; Editing by Matthew Lewis and Sandra Maler)