() President Donald Trump on Thursday threatened Mexico with sanctions and tariffs in a dispute over water sharing between the two countries, accusing Mexico of breaking an 81-year-old treaty and “stealing the water from Texas farmers.”

Under the 1944 treaty, Mexico must send 1.75 million acre-feet of water to the U.S. from the Rio Grande through a network of interconnected dams and reservoirs every five years. An acre-foot of water is enough to fill about half an Olympic-sized swimming pool.

The current five-year cycle is up in October, but Mexico has sent less than 30% of the required water, according to data from the International Boundary and Water Commission.

Texas Agriculture Commissioner Sid Miller claimed Mexico has the available but refuses to send it to the U.S.

“Rainfall is really not the issue with Mexico paying their water debt,” he told . “What they’ve (Mexico) done is dammed up the rivers and tributaries that flow into the Rio Grande, and they’re holding the water back.”

Miller claimed to have seen “air photographs” of Mexican lakes at full capacity but did not specify which ones.

Mexican President Claudia Sheinbaum, in response to Trump, said on X that Mexico has been complying with the treaty “to the extent water is available” amid three years of drought.

Mexico sent a proposal to U.S. officials on Wednesday, Sheinbaum said, to address the water supply to Texas, which includes short-term actions. Sheinbaum said she instructed her environment, agriculture and foreign ministers to immediately contact U.S. officials.

“I am sure, as on other issues, an agreement will be reached,” Sheinbaum said.

Reuters contributed to this report.