The United States as a signatory country of the Budapest Memorandum providing guarantees for Ukraine's security in exchange for its renunciation of nuclear weapons should participate in negotiations concerning Crimea and the situation in Donbas, Ukrainian Foreign Minister Pavlo Klimkin has said.

"Of course, we need U.S. support to restart negotiations between the signatories of the Budapest Memorandum," he said, speaking in the U.S. Senate.

According to the minister, "the United States should play a key role in the negotiations on Donbas and Crimea."

Kyiv, accusing Russia of the annexation of Crimea and aggression in Donbas, points to Moscow's violating the Budapest Memorandum and a lack of proper reaction from other signatories.