Russian intelligence services are building up their presence in Mexico for spy operations targeting the United States, a return to Cold War tactics by an increasingly aggressive regime, according to U.S. officials and former intelligence officers.

Russia has added dozens of personnel to its embassy staff in Mexico City in the past few years, even though Moscow has only limited trade ties with the country. U.S. officials say the trend is concerning and believe the extensive buildup is aimed at bolstering the Kremlin’s intelligence operations targeting the U.S., as well as its propaganda efforts aimed at undermining Washington and Ukraine.

The Biden administration has raised the issue with the Mexican government, a U.S. official told NBC News. “Russia has really invested in Mexico in terms of seeking to extend their presence,” the official said.

The Mexican Embassy and the Russian Embassy did not respond to a request for comment.

CIA Director William Burns said earlier this month his agency and the U.S. government are “sharply focused” on Russia’s expanding footprint in Mexico, which he said was partly the result of Russian spies being expelled from foreign capitals after Moscow’s full-scale invasion of Ukraine.

“Part of this is a function of the fact that so many Russian intelligence officers have been kicked out of Europe. … So they’re looking for places to go and looking for places in which they can operate,” Burns said in London this month when asked about suspected Russian spying out of Mexico. “But we’re very sharply focused on that.”

Russia’s actions in Mexico reflect a more aggressive posture by its intelligence services across multiple fronts, as the Kremlin seeks to silence critics abroad, undermine support for Ukraine and weaken Western democracies, former intelligence officials said. That approach has included sabotage and attempted sabotage in Europe, assassination plots, relentless cyberattacks and large-scale global disinformation campaigns, according to U.S. and European officials.

“They’re willing to take much higher risks now than maybe they would have in the immediate post-Cold War,” said Paul Kolbe, who worked for 25 years as an operations officer in the CIA, with postings in Russia, the Balkans and elsewhere.

Air Force Gen. Glen VanHerck, head of U.S. Northern Command, told the Senate Armed Services Committee in March 2022 that Russia’s GRU military intelligence service had a massive presence in Mexico.

“I would point out that the largest portion of GRU members in the world is in Mexico right now. Those are Russian intelligence personnel, and they keep an eye very closely on their opportunities to have influence on U.S. opportunities and access,” VanHerck said.

Since VanHerck’s comments, which came shortly after Russia launched its full-scale invasion of Ukraine, Russia has continued to expand its footprint at the embassy in Mexico City, securing accreditation from the Mexican authorities.

Asked about the general’s comments at the time, Mexico’s President Andrés Manuel López Obrador said he didn’t have information about it and that Mexico is “a free, independent, sovereign country.”

Even though Mexico has built up extensive trade ties with the United States over decades, it has traditionally tried to steer away from fully aligning itself with Washington’s foreign policy and has maintained friendly relations with Russia and Cuba.

Trotsky and the ice ax

Russian spies — and their American informants — have a long history in Mexico.

In 1940, the Kremlin hunted down one of its revolutionary leaders and communist ideologues, Leon Trotsky, who had been ousted from power after falling out with Soviet dictator Joseph Stalin.

Trotsky, who at one point was expected to succeed Vladimir Lenin as leader of the Soviet Union, had lived in hiding, moving from country to country before settling in Mexico.

But on Aug. 20, 1940, Trotsky allowed a Spanish communist he believed was a friend into his private study. The visitor, Ramon Mercader, had hidden a shortened ice climbing ax under his suit jacket, suspended by a string. He attacked Trotsky, who died from his wounds the following day.

John Sipher, who worked in the CIA’s clandestine service for 28 years, said Russia has always told Americans offering to spy for Moscow to head to Mexico.

“For decades, if Americans reached out and volunteered to spy for Moscow, they would be told to travel to Mexico City. The environment for Russian intelligence in the U.S. is difficult,” Sipher said.

In the 1970s, Christopher Boyce, a college student working at the TRW aerospace company in the affluent suburbs of Los Angeles, and his high school friend Andrew Daulton Lee, were found guilty of providing U.S. satellite secrets to the Soviets. Over two years, Lee traveled to Mexico City to deliver classified information to agents at the Soviet Embassy and collect money for him and Boyce. Their case became the subject of a book and a major Hollywood film, “The Falcon and the Snowman.”

Harold “Jim” Nicholson, a high-ranking CIA officer convicted in 1997 of passing secrets to Moscow, was serving his sentence for espionage when he tried to use his son to collect his “pension” payments from Russian agents in Mexico. His son was eventually arrested and convicted in 2010, and his father was convicted for a second time.

Two years ago, a prominent Mexican scientist, Hector Cabrera Fuentes, pleaded guilty to being co-opted by Russian agents into surveilling a U.S. government informant living in Miami. Fuentes was leading a double life with two families on two continents, and Russian spies used that to coerce Fuentes into cooperating.

A ‘benign environment’

Unlike the U.S., where Russian intelligence is under intense scrutiny from the FBI and consulates have been shuttered, Mexico offers a convenient, lower-risk setting for Moscow to oversee agents in the U.S. and stage other operations, according to former intelligence officers.

“It’s a very benign environment for the Russians to operate in,” said Douglas London, a retired senior CIA operations officer and the author of a memoir, “The Recruiter.” “It makes a lot of sense, and it’s why the Russians are there in such big numbers.”

The Russians would likely want to use Mexico’s proximity but relative safety beyond U.S. law enforcement’s reach to support both American agents and Russian officers operating under “deep cover” in the U.S., he said.

An American agent working for Russian intelligence could travel back and forth across the U.S.-Mexico border and meet up with Russian handlers to get paid, debriefed, resupplied and receive training on communication methods or other spycraft, London and other former CIA officers said.

Russian intelligence could conceivably also take advantage of Mexico’s proximity to target Putin’s political enemies inside the U.S., former intelligence officers said.

The Russians likely would have little interest in having operatives try to cross the southern border illegally with migrants, London said. “They want any travel to be aboveboard, look clean, to be unnoticeable,” he said.

But Russian intelligence agencies would have the option to work with cross-border criminal networks if it suited a particular mission, and if they were ready to tolerate a much higher risk, according to other former intelligence officers.

Part of the mandate of the GRU is to prepare possible sabotage operations in the event of a war with the U.S., and Mexico would be a practical base for such contingency plans, former intelligence officers said.

The perception of a large Russian spying bastion in Mexico is useful as a propaganda tool as well, to exaggerate Moscow’s capabilities and fuel a perception of a supposedly “uncontrollable border,” Kolbe said.

U.S. officials also are concerned about Russia’s effort to manipulate the information landscape in Mexico, seeking not only to undercut international support for Ukraine but also to sow social divisions. Russia has expanded its state-funded media outlet RT in Mexico and run a large advertising campaign for the channel.

In April, the Russian ambassador to Mexico posted a false report by Russian state media claiming that the U.S. was recruiting members of drug cartels from Mexico and Colombia to send them to fight in Ukraine. The baseless account was picked up by some Mexican news organizations.