The United States does not recognize Russia's "referendum" of March 16, 2014, and accuse Russian authorities of violation of rights of peninsular residents, Acting Spokesperson Mark C. Toner has said.

Toner said in a statement that "the United States does not recognize Russia's 'referendum' of March 16, 2014, nor its attempted annexation of Crimea and continued violation of international law."

"Russia then staged an illegitimate referendum in which residents of Crimea were compelled to vote while heavily armed foreign forces occupied their land," he said.

"Over the past three years, Russian occupation 'authorities' in Crimea have engaged in a campaign to suppress dissent. In Russian-occupied Crimea, human rights monitors have documented enforced disappearances, extrajudicial killings, torture and punitive psychiatric hospitalizations," reads the statement.

"Crimean Tatars, ethnic Ukrainians, pro-Ukrainian activists, and independent journalists have been subjected to politically motivated prosecution and face ongoing repression," the U.S. Department of State said.

"We call on Russia to cease its attempts to suppress freedom of expression, peaceful assembly, association, and religion," reads the statement.

"Our Crimea-related sanctions will remain in place until Russia returns control of the peninsula to Ukraine," the U.S. Department of State said.