Leaders of Ukraine hope for further fruitful cooperation with the U.S. under the administration of President-elect Donald Trump and also hope that Washington's support of Kyiv will remain at the current level, President of Ukraine Petro Poroshenko has said.

"Today we have also thoroughly exchanged our thoughts with Mr. Vice-President on the further establishment of the U.S.-Ukrainian strategic partnership. We respect the democratic choice of the American people and are ready for effective and fruitful cooperation with the new administration," he said at a joint briefing with U.S. Vice-President Joseph Biden in Kyiv on Monday.

'The present-day aggressive Russia' is a threat to the U.S. and Ukraine, he said. "Russia invaded Ukraine and occupied a part of Donbas and Crimea. Crimea is Ukraine, and we are grateful to representatives of the next administration for firmly maintaining this stance," he said.

In this light, the Ukrainian president said that members of the Trump team had sent inspiring messages regarding their stance on Ukraine.

"I welcome the first inspiring messages sent during Senate hearings of nominees for the positions of state secretary, [Rex] Tillerson, and defense secretary, [James] Mattis," Poroshenko said.