A firefight involving U.S. Coast Guard personnel along the Mexican border has sparked a dispute between Washington and Mexico City over where the gunfire originated, even as the two countries continue coordinating border security operations.

The Coast Guard told Fox News Digital that personnel conducting joint interdiction operations near Garceno, Texas, came under fire from the Mexican side of the border Sept. 26 and returned fire. No injuries or damage to Coast Guard vessels or equipment were reported, and the incident remains under investigation.

After U.S. Ambassador to Mexico Ronald Johnson publicly announced that Coast Guard personnel had come under fire, Mexican President Claudia Sheinbaum demanded evidence that the shots originated from her country's territory.

"We asked for all the evidence because we have no evidence," Sheinbaum told reporters in Mexico City, saying Mexican security forces had not detected shots originating from their territory.

MEXICO VOWS US WILL PAY AFTER ICE FATALLY SHOOTS ILLEGAL MIGRANT WHO ALLEGEDLY ATTEMPTED TO RAM AGENT WITH CAR The State Department, however, told Fox News Digital that information about the shooting had been shared with Mexican authorities. "U.S.

Coast Guard personnel were fired upon from Mexican territory on September 26, and we have shared the available information with the Government of Mexico through official channels," a State Department spokesman said.

The department did not specify what was shared or when, and U.S. officials have not publicly identified the shooters or detailed how they determined the gunfire's origin.

TRUMP DHS HITS 16 STRAIGHT MONTHS WITH 0 RELEASES AT THE BORDER The incident occurred amid Operation River Wall, a Coast Guard initiative launched in October 2025 to deter illegal migration, drug smuggling and other threats along approximately 300 miles of the Rio Grande.

"Over the past year, the Coast Guard has expanded operations in the region, deploying more than 1,000 personnel and more than 30 assets," a Coast Guard spokesperson told Fox News Digital, referring to "Operation Sable".

Separately, Mexico's Navy Ministry, led by Secretary Raymundo Morales-Angeles, said 159 "Naval elements", 11 vehicles and two drones were deployed to the Tamaulipas sector.

U.S. Northern Command (NORTHCOM) separately told Fox News Digital that American troops are being repositioned to the Rio Grande Valley in anticipation of a seasonal increase in attempted illegal border crossings.

Asked whether Mexico had received evidence from U.S. authorities or launched its own investigation, a representative for Mexican Ambassador to the U.S. Roberto Lazzeri Montaño referred Fox News Digital on Monday to Sheinbaum's more recent remarks addressing the incident.

Sheinbaum said Mexico's military ministry "maintains" communication with NORTHCOM and the Coast Guard and that a "mirror operation" coordinated with the U.S. remains active.

"We want to have a good relationship with the United States within the framework of our sovereignty, our territorial integrity, mutual trust, and coordination without subordination," she said. Her response did not explicitly confirm whether Mexico had received the information Washington says it shared. Fox News Digital also contacted Sheinbaum's office for comment.

LATIN AMERICA’S CONSERVATIVE SHIFT FACES ITS BIGGEST TEST YET IN BRAZIL ELECTION Santiago Vidal Calvo, a Venezuelan-born immigration analyst at the Manhattan Institute, told Fox News Digital that Sheinbaum's approach to border security is shaped by pressure from Washington and a broader Latin American shift toward right-wing governments.

"She has that regional pressure [and] she has the international pressure from the United States" to cooperate on security matters, Calvo said.

He suggested Sheinbaum's demand for evidence of the Coast Guard shooting could reflect pressure within her own political coalition to justify working with the Trump administration.

"She has a high bar to meet if she wants to ally with the Trump administration internally within her own party and her own government," Calvo said.

"We've got to understand this through the lens of what is going on in Latin America. I do think that Sheinbaum's position is substantially different today than it was when Trump got elected," Calvo said.

His assessment reflects Sheinbaum's ties to the left-wing Morena Party and the political legacy of her predecessor, former President Andrés Manuel López Obrador, commonly known as AMLO.

Calvo characterized Sheinbaum as the "last bastion of Latin American socialism," arguing that she could face additional regional pressure if Flávio Bolsonaro defeats President Luiz Inácio Lula da Silva in Brazil's upcoming presidential runoff.

Calvo suggested that the rightward shift among South American governments could increase pressure on Sheinbaum to cooperate with Washington on security matters.

He said she may face questions about whether "you're the only president of Latin America who's not cooperating with the United States in terms of security?" "Both of those things do lead to a more serious border campaign for both countries," Calvo said.

"I have no doubt that the change in South America from left-leaning governments to right-leaning governments has to do with the Trump administration's policy in Latin America," he added.

US CHARGES MEXICAN GOVERNOR, TOP OFFICIALS IN CARTEL CONSPIRACY AS MEXICO FIRES BACK OVER PROOF Border security policy analyst Simon Hankinson told Fox News Digital that gunfire near the Rio Grande is not unprecedented, citing accounts he heard during previous visits to the border.

Hankinson said cartel involvement was possible but expressed doubt that Mexican military personnel would deliberately fire across the border unless they were acting against orders.

SIGN UP TO GET THE POLITICS NEWSLETTER "I think these two politicians can cooperate, they can agree on some things, even if they don't agree on socialism versus capitalism and some other ideological issues," he added. The Coast Guard said the circumstances surrounding the incident remain under investigation.