"The Assistant Secretary of State for European and Eurasian Affairs confirmed willingness to keep on supporting Ukraine's efforts to restore sovereignty and territorial integrity and, if necessary, to increase the price of the continuation of aggression against the Ukrainian state for Moscow," the Ukrainian presidential press service reported following a meeting between President Petro Poroshenko and Mitchell.

In addition, the parties thoroughly discussed a set of issues of Ukraine-U.S. bilateral relations and coordinated priorities within their enhancement in the best interests of the two parties and joint protection and promotion of freedom and democracy, the rule of law and human rights.

Read alsoU.S. House of Representatives backs $700 bln defense policy bill – mediaThe importance of new approaches and bold initiatives for the replenishment of strategic partnership between Ukraine and the United States was noted – from the enhanced political, trade, economic and energy interaction to the intensification of defense and security partnership between the parties.

Poroshenko thanked the American side for its assistance and significant contribution to the development of a new Ukrainian army amid Russian aggression.

Mitchell stressed the importance of his visit to Ukraine and assured that the United States would further support Ukraine in its endeavors to develop and strengthen the country, as well as in the further coordination of efforts aimed to ensure a reliable and efficient international support for Ukraine.

"What you and your team have achieved in a very short period of time is remarkable. It is phenomenal that so much has been made over the past three years," he said.