President Donald Trump threatened to impose tariffs, and possibly sanctions against Mexico, if it continues to rob South Texas farmers of Rio Grande water promised under a decades-old treaty.

In a post on Truth Social on Thursday, Trump proclaimed that Mexico owes Texas 1.3 million acre-feet of water under the 1944 Water Treaty, though Mexico was violating their obligation.

“This is very unfair, and it is hurting South Texas Farmers very badly,” the president wrote. “Last year, the only Sugar Mill in Texas CLOSED, because Mexico has been stealing the water from Texas Farmers. Ted Cruz has been leading the fight to get South Texas the water it is owed, but Sleepy Joe refused to lift a finger to help the Farmers. THAT ENDS NOW!”

Trump continued, saying he will make sure Mexico does not violate treaties with the U.S. and hurt farmers in Texas.

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“Just last month, I halted water shipments to Tijuana until Mexico complies with the 1944 Water Treaty,” he said. “My Agriculture Secretary, Brooke Rollins, is standing up for Texas Farmers, and we will keep escalating consequences, including TARIFFS and, maybe even SANCTIONS, until Mexico honors the Treaty, and GIVES TEXAS THE WATER THEY ARE OWED!”

Texas farm groups warned of a disastrous season ahead of them for citrus and sugar, last year, as Mexican and U.S. officials tried to resolve a dispute over the 1944 water treaty that supplies U.S. farmers with critical irrigation.

The two countries have tussled over the treaty before, but the drought-driven water shortages were the most severe in nearly 30 years.

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Under the treaty designed to allocate shared water resources, Mexico is required to send 1.75 million acre-feet of water from the Rio Grande to the U.S. over a five-year cycle.

Texas’s half-billion-dollar citrus industry is heavily dependent on water from Mexico, especially with drought conditions growing more severe in the region. In fact, Texas is the third-largest citrus state behind California and Florida.

Last month, the Bureau of Western Hemisphere Affairs posted that it was denying a request from Mexico to deliver water to Tijuana.

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“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 agency wrote on X. “As a result, today for the first time, the U.S. will deny Mexico’s non-treaty request for a special delivery channel for Colorado River water to be delivered to Tijuana.”

The day before, Sen. Ted Cruz, R-Texas., said South Texas was facing a water crisis, which he called a “man-made crisis.”

He also noted that he was leading the fight in the Senate to hold Mexico accountable and abide by the treaty to deliver water to farmers in South Texas.

He shared the Bureau of Western Hemisphere Affairs’ post, calling the move, “excellent.”

“As I said yesterday, this option is absolutely what the Trump administration needs to pressure Mexico to fulfill its obligations under the 1944 Water Treaty,” Cruz wrote on X. “Texas farmers are in crisis because of Mexico’s noncompliance. I will work with the Trump administration to pressure Mexico into complying and to get water to Texas farmers.”

Reuters contributed to this report.