MOSCOW- Prices of Russian wheat exports fell last week after a higher than expected U.S. Department of Agriculture (USDA) estimate of this year's U.S. corn crop caused a sharp slide in Chicago grain futures, a global benchmark for the market, analysts said.

Black Sea prices for wheat with 12.5% protein content fell $1 to $193 a tonne on a free on board (FOB) basis by the end of last week, Russian agricultural consultancies SovEcon and IKAR said.

Barley prices rose by $2 to $181 a tonne, SovEcon added.

Russian wheat exports fell sharply last week compared with a week earlier, SovEcon said, citing customs data. It currently sees August wheat, barley and maize exports at 4.2 million tonnes, which is a relatively low amount for this time of the season.

The period between August and October is traditionally the most active for Russian grain exports.

Russia has exported 6.0 million tonnes of grain since the start of the 2019/20 season, 12% less than in the same period of the previous year, SovEcon said. That figure included 4.9 million tonnes of wheat.

Meanwhile, the harvesting campaign in Russia sped up last week due to dry weather. The country has already harvested 69.1 million tonnes of grain - including 53.7 million tonnes of wheat - from 45% of the area. urn:newsml:reuters.com:*:nL5N25F2PK

"The European part of Russia is expected to remain mainly dry within two weeks which will help the harvesting campaign," SovEcon said. Rains expected in the Siberian Altai region during the period could help late wheat sowings, it said.

On the domestic wheat market, prices for third-class wheat were steady at 10,425 roubles ($156) a tonne at the end of last week in European parts of Russia on an ex-works basis, SovEcon said. Ex-works does not include delivery costs.

Sunflower seed prices rose by 75 roubles to 20,100 roubles a tonne, while domestic sunflower oil prices jumped by 500 roubles to 46,500 roubles a tonne, SovEcon said. FOB export prices for sunflower oil fell by $10 to $735 a tonne.

IKAR said its price index for white sugar from southern Russia fell to $357 a tonne from $372 a week earlier.

($1 = 66.9300 roubles)

(Reporting by Olga Popova and Polina Devitt; writing by Polina Devitt; editing by Susan Fenton) ((Polina.Devitt@thomsonreuters.com; +7 495 775 12 42; Reuters Messaging: polina.devitt.reuters.com@reuters.net))