Ukraine has marked the 85th anniversary of the Stalin-era famine, known as the Holodomor, in which millions of people died of starvation.
The anniversary was also marked by U.S. criticism of what Washington called "ongoing aggression in eastern Ukraine" by Russia and "attempts" by Moscow "to destroy the identity and Western aspirations of the people of Ukraine."
Moscow responded by rejecting critics who describe the Holodomor exclusively as an act of genocide against the Ukrainian people.
Ukrainian President Petro Poroshenko and his wife, Maryna, on November 24 laid bouquets fashioned from wheat stalks and red flowers at a memorial to the victims of the Holodomor on Kyiv's Mykhailivska Square.
Poroshenko, in a statement posted on his Facebook page, also said the Holodomor was an "artificial" famine and a terrible crime committed by Soviet authorities in the early 1930s.
"In the name of Ukraine's preservation we must always remember the terrible crimes committed by the communist regime on Ukrainian lands," he said.
The Holodomor took place in 1932 and 1933 as Soviet authorities forced peasants in Ukraine to join collective farms by requisitioning their grain and other food products.
Estimates of the famine's death toll range from 3 million to 7 million.
Ukraine marks the Day of Remembrance of the Victims of the Holodomor each year on the fourth Saturday of November to commemorate those who died during the tragedy, which many Ukrainians consider as an act of genocide aimed at wiping out Ukrainian farmers.
The Russian government denies there was any systematic effort by Soviet-era authorities to target Ukrainians, arguing a poor harvest at the time wiped out many in other parts of the Soviet Union.
On November 24, the Russian Foreign Ministry described the famine as a "major humanitarian catastrophe" that also affected Russians, Kazakhs, and others.
"Attempts to present those tragic events exclusively as an act of 'genocide of the Ukrainian people' have nothing in common either with the restoration of justice or historical facts," the ministry said on its VKontakte page.
WATCH: One woman reveals how her great-grandfather secretly photographed the suffering in the city of Kharkiv.
Ahead of the commemorations, the U.S. State Department said on November 23 the "man-made famine" was "one of the most atrocious acts of the 20th century."
The. State Department also said the victims were "deliberately starved to death by the regime of Josef Stalin."
"The Soviet Union's barbaric seizure of Ukrainian land and crops was undertaken with the deliberate political goal of subjugating the Ukrainian people and nation," it said.
The State Department also pointed to Russia's "ongoing aggression" in eastern Ukraine, where fighting between Ukrainian government forces and Moscow-backed separatists has left more than 10,300 dead since April 2014.
"Today Ukrainians are once again dying as a result of Russia's attempts to destroy the identity and Western aspirations of the people of Ukraine," the statement added, citing Moscow's "ongoing aggression in eastern Ukraine."
However, Russia "will not vanquish the resilient Ukrainian spirit, nor dampen Ukrainians' desire for a better future," the State Department added, reaffirming the United States' "unwavering support" for Ukraine's national sovereignty and territorial integrity.
In a video posted on Twitter to mark the Holodomor anniversary, U.S. Ambassador Marie Jovanovich said, "Even during the darkest times, the Ukrainian people have continued to struggle for pace, freedom, and democracy with dignity."
"The United States stands with the people of Ukraine," she added.
Along with Ukraine, at least 15 other countries have officially recognized the Holodomor as "genocide" -- but not the United States.
On October 3, the U.S. Senate adopted a nonbinding resolution recognizing that Stalin and those around him committed genocide against the Ukrainians in 1932–33.
The European Union describes the Ukrainian famine an "appalling crime."
Relations between Moscow and Kyiv -- as well as its Western backers -- have deteriorated dramatically after Russia seized Ukraine's Crimean Peninsula in March 2014 and shortly thereafter began supporting separatists in the eastern Ukrainian regions of Donetsk and Luhansk.