Cuba’s Foreign Affairs Minister Bruno Eduardo Rodriguez Parrilla addresses the 80th United Nations General Assembly (UNGA), at the U.N. headquarters in New York City, U.S., September 27, 2025. REUTERS/Caitlin Ochs

By Humeyra Pamuk

WASHINGTON (Reuters) -President Donald Trump's administration is mobilizing U.S. diplomats to lobby against a U.N. resolution calling on Washington to lift its decades-long embargo on Cuba, in part by sharing details of Cuba’s support for Russia’s war in Ukraine, according to an internal State Department cable seen by Reuters.

As part of the administration's campaign, U.S. diplomats will tell countries that the Cuban government is actively supporting Russia's invasion of Ukraine with up to 5,000 Cubans fighting alongside Moscow's forces.

The October 2-dated unclassified cable sent to dozens of U.S. missions directed American diplomats to urge the governments to oppose the non-binding resolution, which has passed in the U.N. General Assembly by wide margins year after year since 1992.

Officials at the Permanent Mission of Cuba to the United Nations did not immediately respond to a request for comment for this story.

Last year, the General Assembly adopted the resolution with 187 countries voting in favor. The United States and Israel were the only countries that voted against it, while Moldova abstained.

Since returning to office in January, Trump has doubled down on sanctions, returning Cuba to a U.S. list of state sponsors of terrorism, tightening financial and travel restrictions and sanctioning third-country nationals who host Cuban doctors.

Trump has also recently toughened his stance towards Moscow, threatening financial penalties against buyers of Russian oil and allowing U.S. intelligence agencies to share information with Ukraine to help its attacks on energy assets inside Russia.

The cable said that the U.N. resolution was "incorrectly" blaming the United States for Cuba's problems which it said were caused by Cuba's "own corruption and incompetence." It added that the objective of this push was to demonstrate the administration's opposition, significantly reducing the number of "yes" votes.

""No" votes are preferred but abstentions or absent/not voting are also useful," the cable said, adding that Washington needed "allies and like-minded partners" in this push.

The United States has piled dozens of new sanctions on the Communist-run Caribbean island since a trade embargo was put in place following Fidel Castro's 1959 revolution.

The U.N. vote can carry political weight, but only the U.S. Congress can lift the Cold War-era embargo.

The Cuban government blames U.S. sanctions for the grueling crisis the country is mired in, the worst economic downturn in decades characterized by shortages of basic goods, collapsing infrastructure and runaway inflation.

The State Department said Cuba was using the annual U.N. resolution as a mechanism to victimize itself and that it did not deserve the support from America's democratic allies.

"The Trump Administration will not remain on the sidelines or support an illegitimate regime that undermines our national security interests in our region," a State Department spokesperson said in emailed comments on Saturday.

CUBAN MERCENARIES IN UKRAINE

For years, U.S. tactics to weaken support for the non-binding U.N. resolution have focused on the legality of the embargo, how the U.S. provided exceptions for food and medicine and highlighted Cuba's human rights, the cable said.

All of these approaches have failed to influence the vote, it added. The cable provided nearly two dozen talking points, many of which accused Cuba of squandering its limited resources, denying its people basic human rights and being a threat to international peace.

Cuba and its President Miguel Diaz-Canel were actively supporting Russia's war in Ukraine, one of the talking points said.

"After North Korea, Cuba is the largest contributor of foreign troops to Russia's aggression, with an estimated 1000-5000 Cubans fighting in Ukraine," the cable said.

The State Department spokesperson declined to provide further details on the Cuban fighters but said Washington was aware of the reports that they were fighting alongside Russian troops in Ukraine.

"The Cuban regime has failed to protect its citizens from being used as pawns in the Russia-Ukraine war," the spokesperson said.

In recent weeks, Ukrainian officials warned U.S. lawmakers about the growing scale of recruitment of Cuban mercenaries by Russia to fight in Ukraine.

The cable also accused the Cuban government of undermining democracies in the Western Hemisphere, as tensions have been mounting between Washington and Venezuela, Cuba’s most important political and economic ally. The U.S. military has carried out strikes in the Caribbean on boats out of Venezuela that it claimed were carrying drugs. The latest U.S. attack took place on Friday.

On Wednesday, Cuban Foreign Minister Bruno Rodriguez called for the United Nations to stop the United States from starting a war in the region. He said fighting drug trafficking in the name of U.S. national security was a “crude and ridiculous pretext” for aggression.

(Reporting by Humeyra Pamuk Editing by Don Durfee and Diane Craft)