NEW YORK, Oct 9 (Reuters) - Chicago corn and soybean futures on Monday gave up overnight gains as traders shifted focus to the harvest pace in the American Midwest from conflict in the Middle East.

The most actively traded corn futures contract on the Chicago Board of Trade (CBOT) was down about 0.9% at $4.87-1/2 a bushel at 11:25 a.m. CDT (1625 GMT), after climbing to $4.97 overnight. CBOT soybeans rallied to $12.77-1/2 before falling back to down about 0.4% at $12.61.

The bloodiest fighting in years between Israelis and Palestinians that erupted over the weekend sent crude oil prices up over $3, a rally that lifted agricultural commodities, briefly.

"I think the focus also started to shift back to what's ahead of us here in the U.S.," said Jerry Gidel, a grains analyst and owner of Midland Research.

Due to a federal holiday on Monday, a weekly U.S. Department of Agriculture (USDA) report on the corn and soybean harvest has been delayed to Tuesday.

On Thursday, USDA will release a monthly report on grain supplies and demand. Analysts expect the USDA to lower its U.S. corn and soybean harvest estimates, and traders are rebalancing their positions ahead of the data.

Soybean prices remain near three-month lows and corn is hovering at lows not seen since January 2021. Both are held in check by weak export demand, exacerbated by a strong dollar .

A glut of soybeans from Brazil has meant tightening U.S. soybean stockpiles have not buoyed prices.

Benchmark CBOT wheat prices were up about 0.6% at $5.72 a bushel, with December futures briefly crossing above the contract's 20-day moving average before falling back below it. Prices had surged more than 2.1% overnight after Palestinian militants launched an attack from the Gaza Strip and Israel retaliated with airstrikes on the coastal enclave. (Reporting by Zachary Goelman in New York City; Additional reporting by Michael Hogan in Hamburg, Peter Hobson in Canberra and Richard Chang)