CHICAGO, March 18 (Reuters) - U.S. wheat futures rose more than 2% on Monday as Russia’s weekend attacks on Ukrainian ports underscored risks to exportable grain supplies from the Black Sea region, analysts said.

Short-covering added momentum. Commodity funds hold large net short positions in Chicago Board of Trade (CBOT) wheat, corn and soybean futures, leaving the market prone to short-covering rallies.

Still, soybean futures fell as the Brazilian harvest progressed, spurring farmer sales of the oilseed. CBOT corn futures inched lower in choppy trade.

As of 12:33 p.m. CDT (1733 GMT), CBOT May wheat was up 12-3/4 cents at $5.41-1/3 per bushel. May soybeans were down 7-1/4 cents at $11.91 a bushel and May corn was down 1-1/2 cents at $4.35-1/4 a bushel.

Wheat rose after Russian air attacks damaged agricultural enterprises and destroyed several industrial buildings in the Black Sea port of Odesa. The Black Sea port city of Mykolaiv was also hit.

Sporadic Russian attacks against Ukrainian ports have drawn limited reaction from grain markets in recent months as they have not disrupted large Ukrainian exports through a Black Sea corridor. However, Ukrainian strikes against Russian oil refineries and Vladimir Putin's re-election as Russia's president raised fears that tensions might escalate.

"Following Ukraine’s attacks on Russian oil refineries last week, concern that Russia could undertake more intensive attacks on Ukrainian ports is returning," said Matt Ammermann, StoneX commodity risk manager.

Soybean futures retreated from a six-week high set last week as combines continued to roll in Brazil, the world's top producer and exporter. Brazil's soybean harvest reached 63% of the planted area as of last Thursday, agribusiness consultancy AgRural said, up 8 percentage points from the previous week and just ahead of the year-ago pace of 62%.

"There has been considerable farmer selling down in Brazil because of higher (cash) basis levels, plus a little rally (in CBOT futures) here last week," said Jack Scoville, vice president of the Price Futures Group in Chicago.

(Reporting by Julie Ingwersen; additional reporting by Michael Hogan in Hamburg and Naveen Thukral in Singapore; editing by Christina Fincher)