American officials and former intelligence officers told NBC News that Russian intelligence is "working to strengthen its presence in Mexico for the purpose of conducting espionage operations targeting the United States," which represents a "return to Cold War tactics" that were prevalent before the collapse of the Soviet Union.

Russia has added dozens of personnel to its embassy in Mexico City in recent years, despite having limited trade relations with Mexico, according to the network.

U.S. officials indicated that this trend is "concerning," noting that the increase in Russian staff "aims to enhance the Kremlin's intelligence operations targeting the United States, as well as its propaganda efforts to undermine Washington and Kyiv."

The Biden administration has raised the issue with the Mexican government, according to a source who spoke to NBC News, adding: "Russia has really invested in Mexico in terms of seeking to expand its presence."

The Mexican embassy and the Russian embassy in Washington did not respond to requests for comment sent by NBC News.