The controversial buoys placed by the US state of Texas in the Rio Grande river to deter border crossings are almost all floating in what is actually Mexican territory, according to a topographical survey.
About 79 percent of the structure, which consists of a string of orange buoys, is floating on the Mexican side of the river, according to the International Boundary and Water Commission.
That leaves just 208 feet of the 995-foot (300 meter) barrier in US waters.
The survey was filed in court on Tuesday as part of a lawsuit by the US Department of Justice against Texas over the barrier.
The buoys were installed in the river at a popular migrant crossing point in July on the instructions of conservative Texas Governor Greg Abbott, along with large razor-wire barriers on shore, sparking a rebuke from both Washington and Mexico City.
The US Justice Department says the buoys illegally obstruct river navigation and lack federal authorization.
Mexican President Andres Manuel Lopez Obrador has previously said that the barriers violate his country’s sovereignty.
Last week, at a meeting in Washington, US Secretary of State Antony Blinken and Mexican Foreign Minister Alicia Barcena announced that a working group would be formed to address the issue.
Barcena had also complained that a large section of buoys were on the Mexican side of the river.
Last week a dead body was found caught in the buoys, igniting further controversy over them.