Russian presidential aide Ushakov said in a live program on Russia's First Channel TV that Russia expounded its principled position on the Ukrainian issue during talks with US officials in Riyadh, the capital of Saudi Arabia, on the 18th, stressing the need to consider the root causes of the conflict. The two sides agreed to set up a special group to conduct in-depth and thorough discussions on all the details of the Ukrainian issue. Ushakov also said that before the inauguration of US President Trump, Russia-US relations were at an unprecedented level. Bilateral relations recently achieved a "unique development" after a phone call between the two presidents, and the two sides agreed to cooperate on many issues on the agenda.