An American military operation in Venezuela killed 32 Cuban officers over the weekend, the Cuban government said Sunday in the first official acknowledgement of the deaths.

The Cuban military and police officers were on a mission the Caribbean country's military was carrying out at the request of Venezuela's government, according to a statement read on Cuban state TV on Sunday night.

What the Cubans were working on in the South American nation was unclear, but Cuba is a close ally of Venezuela's government, and has sent military and police forces to assist in operations for years.

"You know, a lot of Cubans were killed yesterday," U.S. President Donald Trump told reporters aboard Air Force One as he flew Sunday night from Florida back to Washington. "There was a lot of death on the other side. No death on our side."

Cuba's government announced two days of mourning.

"Faithful to their responsibilities for security and defense, our compatriots fulfilled their duty with dignity and heroism and fell after fierce resistance in direct combat against the attackers or as a result of the bombings of the facilities," the official statement added.