* Position squaring ahead of U.S. supply/demand report on Friday
* Hot, dry weather in United States, Europe supports grains prices
SINGAPORE, Aug 11 (Reuters) - Chicago corn and wheat futures retreated on Thursday after hitting more than one-week highs in the previous session on concerns over hot and dry weather conditions in key exporting countries.
Soybeans lost ground after closing almost unchanged on Wednesday.
"Weather forecasters' outlook for the United States next week is little changed, meaning yield downgrades in some regions," said Tobin Gorey, director of agricultural strategy at the Commonwealth Bank of Australia.
The most-active corn contract on the Chicago Board of Trade (CBOT) was down 0.4% at $6.15-3/4 a bushel, as of 0049 GMT, and wheat fell 0.5% to $7.95-1/2 a bushel.
Soybeans slid 0.3% to $14.23-1/4 a bushel.
Parts of the U.S. Midwest received rain in recent days, but heat in the western regions of the farm belt is expected to continue stressing crops.
In Europe, persisting drought and high temperatures are threatening to deepen corn crop losses. Romania finished reaping its wheat crop for the year, and the harvest is 15% to 18% smaller than in 2021, Agriculture Minister Petre Daea said.
Investors in the agricultural markets are adjusting positions ahead of the U.S. Department of Agriculture's (USDA) monthly supply-and-demand report on Friday.
The government is expected to trim its outlook for U.S. corn production, according to a Reuters survey of analysts.
Ukraine's grain, oilseed, vegetable oil exports rose 22.7% in July to 2.66 million tonnes versus June, due to higher wheat and barley shipments, the agriculture ministry said on Wednesday.
Ukraine's grain exports have slumped since the start of the war because its Black Sea ports - a key route for shipments - were closed off, driving up global food prices and prompting fears of shortages in Africa and the Middle East.
July's exports included 412,000 tonnes of wheat, 183,000 tonnes of barley, 1.1 million tonnes of corn, 362,100 tonnes of sunseed and tonnages of other commodities, the ministry said.
However, the ministry said Ukrainian grain exports were down almost 52% year-on-year at 2.2 million tonnes so far in the 2022/23 season.
Commodity funds were net buyers of CBOT corn, wheat, soybean, soyoil and soymeal futures contracts on Wednesday, traders said. (Reporting by Naveen Thukral; Editing by Sherry Jacob-Phillips and Subhranshu Sahu)
