CHICAGO: US wheat futures fell on Friday on a round of technical selling and worries about trade with Mexico, the top importer of US supplies, traders said.

* The benchmark Chicago Board of Trade (CBOT) soft red winter wheat contract turned lower after failing to take out the 3-1/2-month high of $5.21-1/4 it hit on Wednesday.

* US President Donald Trump vowed on Thursday to impose a tariff on all goods coming from Mexico, starting at 5% and ratcheting much higher until the flow of immigrants at the southern US border stopped.

* Declines in K.C. hard red winter wheat futures were limited by concerns that heavy rainfall in the US Plains in recent weeks was cutting into the quality of the crop grown there.

* The most active CBOT soft red winter wheat futures contract rallied 17.7% in May, its biggest monthly gain since June 2017.

* CBOT wheat rose 3.1% this week.

* The US Agriculture Department on Friday morning said that weekly export sales of wheat totaled 564,800 tonnes. Analysts forecasts for weekly export sales ranged from 200,000 tonnes to 600,000 tonnes.