* Wheat futures gained on decreased Russian harvest expectations

* Soybeans fall on pressure from cheaper South American soymeal

* Corn slips on improved U.S. planting weather

CHICAGO, May 28 (Reuters) - Chicago benchmark wheat futures rose on Tuesday, supported by reduced harvest projections in Russia, hitting a 10-month high before paring gains.

Soybean futures turned lower on poor U.S. soymeal competitiveness, while corn contracts eased as U.S. planting weather improved.

Dry weather and bitter frosts have hit key wheat-growing regions in Russia's south, and some 1.5 million hectares (3.7 million acres) of Russian crops have been damaged by frosts, Russia's Grain Union said.

"Crop issues in Russia are the big story of the moment," said Terry Linn, a broker at Linn and Associates. "We've got a really volatile weather trade."

The most-active wheat contract on the Chicago Board of Trade (CBOT) rose 3 cents to settle at $7.00-1/4 per bushel.

Consultancy IKAR on Monday further reduced its estimate for Russian wheat production to 81.5 million metric tons and exports to 44 million tons. Only a month ago, IKAR predicted production of 93 million tons and exports of 52 million tons.

Although some rains are expected in a stretch of southern Russia this week, analysts are unsure whether the moisture will be enough to significantly boost the country's harvest.

Soybean prices tumbled as weakness in U.S. soymeal futures dragged the complex down, due largely to cheaper South American meal exports weighing on the market.

Corn futures gained some support from the rally in wheat prices, though speedy planting progress and dry weather forecasts in the U.S. Corn Belt pressured prices early in the session, traders said.

In the United States, traders will watch for a weekly government report after Tuesday's close to assess the condition of wheat crops and planting progress for corn and soybeans.

CBOT July corn CN24 fell 2-1/4 cents to close at $4.62-1/2 per bushel, while soybean futures fell 18-1/2 cents to $12.29-1/2 per bushel. (Reporting by Heather Schlitz in Chicago. Additional reporting by Gus Trompiz in Paris and Peter Hobson in Canberra; Editing by Rashmi Aich, Will Dunham, Sherry Jacob-Phillips, Chizu Nomiyama and David Gregorio)