UN Secretary-General António Guterres has spoken separately with the Russian and Ukrainian foreign ministers and still believes, "from his own analysis, his own hopes,", that there will be no conflict, said UN spokesman Stephane Dujarric.

The United Nations has no plans to evacuate or relocate out of Ukraine any of its more than 1,600 staff - of which 220 are foreign staff and more than 1,400 are Ukrainian - UN spokesman Stephane Dujarric also said.

During phone calls with Russian Foreign Minister Sergey Lavrov and Ukrainian Foreign Minister Dmitry Kuleba, António Guterres expressed "serious concern" at the escalating tensions.

"He welcomed the ongoing diplomatic discussions to defuse those tensions and underlined, yet again, the fact that there is no alternative to diplomacy," Dujarric said.