Chicago Board of Trade corn futures eased on Monday, pressured by technical selling and position squaring ahead of a key US Department of Agriculture (USDA) crop report due at the end of the week.

Concerns about Middle East tensions following the killing of an Iranian general by the United States cast a bearish tone across grain markets. Investors are taking some risk out of their portfolios, analysts said.

The most-active March corn contract fell to a 3-1/2 week low after breaking through chart support at several key technical levels, including its 20-, 50- and 100-day moving averages.

Traders are awaiting details on the Phase 1 trade agreement Washington and

Beijing struck last month that is expected to increase Chinese buying of US farm goods. Chinese officials will travel to the United States next week to sign the deal.