CHICAGO (Dow Jones)--U.S. corn futures are expected to open lower Tuesday on profit-taking and global economic uncertainty.

Chicago Board of Trade futures are called 4 to 6 cents lower. In overnight trading, December corn was down 4 3/4 cents, or 0.9%, to $5.10 1/2 per bushel.

The market slid late overnight to session lows, due in part to reports of an exchange of gunfire between North and South Korea. That has caused uncertainty in the markets, as has lingering concerns over Ireland's debt crisis.

As a result, investors drove the U.S. dollar higher, which weighed on commodities, analysts said.

Corn prices have been sliding ever since setting a 27-month high of $6.05 early in the month. Market participants, who had built up a massive long position in corn futures, are booking profits as the end of the month and end of the year draw closer, analysts said.

That negative price momentum is sending to the sidelines even those traders who believe a tight supply outlook will send prices to new highs in the long run.

"When the steamroller's rolling, you don't get bulled up," said Jason Britt, president of Central State Commodities.

Britt said that options activity has accelerated the market's decline, as many traders had made bets assuming the market would continue to climb.

Prices are hovering just above key technical support levels, and a slide on Tuesday will likely trigger more technical-based selling, analysts said.

Many traders say that the market's recent high will stand for the rest of the year. But Britt expects that the current liquidation to end this week, and that traders will again focus on the supply and demand outlook.

"Come Monday, a lot of people who had exposure in this market are going to be out of it," Britt said.

Some analysts say the long-term outlook remains supportive. The government projects U.S. supplies will be at their lowest level in 15 years in 2011.

-By Ian Berry, Dow Jones Newswires; 312-750-4072; ian.berry@dowjones.com