Washington (CNN) Secretary of State Mike Pompeo issued a statement Wednesday saying the US "rejects Russia's attempted annexation of Crimea and pledges to maintain this policy until Ukraine's territorial integrity is restored."

"The United States calls on Russia to respect the principles to which it has long claimed to adhere and to end its occupation of Crimea," the statement reads.

Pompeo is also expected to state in congressional testimony Wednesday that the United States will never recognize Crimea as part of Russia, a European diplomat briefed by the State Department told CNN.

Pompeo's declaration comes after President Donald Trump had appeared to cast doubt on his administration's commitment to Ukraine's claims over the peninsula.

Asked by reporters on Air Force One at the end of June whether the United States would recognize Russia's claim on Crimea, Trump ambiguously responded: "We're going to have to see."

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