The State Department said it was the first time that the United States has rejected a request by Mexico for special delivery of water, which would have gone to the border city of Tijuana.

"Mexico's continued shortfalls in its water deliveries under the 1944 water-sharing treaty are decimating American agriculture-- particularly farmers in the Rio Grande valley," the State Department's bureau handling Latin America said in a post on X.

The 1944 treaty, which governs water allocation from the Rio Grande and Colorado rivers, has come under growing strain in recent years due to the pressures of climate change and the burgeoning populations and agriculture in parched areas.

The treaty sets five-year cycles for water deliveries, with the latest set to end in October 2025.

US farmers and lawmakers complain that the neighboring country has waited until the end of each cycle in the past and has come up short in the latest period, as Mexico struggles with drought.

A year ago the last sugar mill in southern Texas shut down, blaming a lack of water deliveries from Mexico.

Lawmakers from Texas have urged consequences on Mexico, saying that the United States has lived up to its own obligations on water-sharing.

"Texas farmers are in crisis because of Mexico's noncompliance," Senator Ted Cruz of Texas wrote on X, praising the State Department's water decision.

"I will work with the Trump administration to pressure Mexico into complying and to get water to Texas farmers."

The water dispute comes as Trump takes a tough approach to Latin American nations, especially on migration.

Trump on returning to office has vowed to end arrivals of undocumented migrants, who largely come from Central America and Venezuela but transit through Mexico.

Trump deployed troops to the border and announced painful tariffs on Mexico, although he has since put them on hold until April 2.