As reported by Censor.NET citing Ukrinform, this was stated by Kurt Volker, the U.S. State Department Special Representative for Ukraine, at the 5th International Forum "The Occupied Crimea: 5 Years of Resistance".
As Volker notes, the U.S. is further interested in negotiating with Russia regarding the restoration of the Ukrainian sovereignty and territorial integrity, primarily in the Donbas area. As of today, Russia has expressed no interest in resolving this issue, but the U.S. hopes it will happen someday.
He also predicts that the humanitarian situation in the region will improve, and the territorial integrity of Ukraine will be restored only when Russia starts a serious talk about ending its aggression in the east of Ukraine.
Volker promised that the U.S. will support Ukraine until it happens.
He also stresses that the United States will never recognize the annexation of Crimea, supporting the recent statement of Mike Pompeo, the U.S. Secretary of State.
Last November, Kurt Volker announced his plan to meet Vladislav Surkov, the aide to Russia's president, sometime in December. However, this meeting was canceled after the Russian military attacked the Ukrainian Navy ships and captured 24 Ukrainian sailors.
He later said that the resumption of this meeting depended on whether the captured sailors would be set free.
Volker last met Surkov in Dubai on Jan. 26, 2018.