President Donald Trump warned that Mexico’s failure to deliver water under the 1944 Water Treaty is harming Texas farmers and could trigger a 5% tariff if 200,000 acre-feet aren’t released by Dec. 31.

Trump said Mexico still owes over 800,000 acre-feet from past years and accused the country of unfairly harming U.S. agriculture.

Texas farm groups have faced severe drought-driven shortages, threatening crops, jobs, and the local economy.

A prior agreement in April had Mexico commit to increasing water flows from Rio Grande tributaries, but shortages persist, Fox News has reported.

The treaty requires Mexico to deliver 1.75 million acre-feet over five years, while the U.S. delivers 1.5 million acre-feet from the Colorado River in return.