"Mexico has been stealing the water from Texas Farmers" and "last year the only Sugar Mill in Texas closed" for lack of water, Trump posted to his Truth Social platform.

He claimed that Mexico was violating a 1944 pact under which the US shares water from the Colorado River in exchange for flows from the Rio Grande, which forms part of the border between the two countries.

"We will keep escalating consequences, including TARIFFS and, maybe even SANCTIONS, until Mexico honors the Treaty," Trump wrote.

The current treaty cycle expires in October and Mexico owes the United States more than 1.55 billion cubic meters, according to the two countries' boundary and water commission.

Washington said on March 20 that it had rejected a request by Mexico for special delivery of water for the first time in response.

Mexico says its lagging deliveries are due to two decades of drought in the Rio Grande basin.

But US farmers and lawmakers complain that their southern neighbor has waited until the end of each five-year delivery cycle and has been coming up short in the latest period.

Mexican President Claudia Sheinbaum said last month that the US complaints were "being dealt with" through the boundary and water commission.

"There's been less water. That's part of the problem," she told reporters.

In November, the two countries signed an agreement aimed at preventing water shortages in parched southern US states with more reliable Mexican deliveries of river water.

Mexico's attempts to comply with the treaty have resulted in civil unrest in the past.

In 2020, farmers in the northern state of Chihuahua seized a dam to prevent the government from supplying water from a reservoir to the United States, leading to clashes between protesters and the National Guard that left one person dead.