Joe Biden condemned Russia’s invasion of Ukraine as a “brutal, needless war” in a speech to the United Nations general assembly.
Mr Biden said Russia “attempted to erase a sovereign state from the map, and has “shamelessly violated the core tenets of the United Nations charter.”
Mr Biden’s remarks came a day after Russian president Vladimir Putin announced a partial mobilisation of 300,000 troops to shore up his forces, which have been pushed back in recent weeks by the Ukrainian army.
Russian-controlled regions in Ukraine’s south are forging ahead with referendums on becoming part of Russia in the coming days, seen by Western officials as a sham process to annex territory captured by war.
Mr Biden noted these latest developments in his remarks, including threats to use nuclear arms made by Mr Putin just last night.
“Just today, President Putin has made overt nuclear threats against Europe...the Kremlin is organizing a sham referendum to try to annex parts of Ukraine, an extremely significant violation of the UN charter,” he said.
The president said the war being prosecuted on the orders of Russian president Vladimir Putin was about “extingiushing Ukraine’s right to exist as a state” and the right of the Ukrainian people to exist.
“Whoever you are, wherever you live, whatever you believe that ... should make your blood run cold,” he said.
Mr Biden said the goal of the United States, Nato, and the other Western allies who’ve united in defence of Ukraine since the invasion began is for the war to end “on just terms” reflecting the fact that countries “cannot seize a nation’s territory by force”.
“The only country standing in the way of that is Russia,” he said.
The president also described Russia’s war on Ukraine as a “shameless” violation of “core tenets of the United Nations charter,” which he said is now under attack “by those who wish to tear it down or distort it for their own political advantage”.
He called for the UN to reform itself, particularly with regard to the Security Council, which he said should be composed of members who will “consistently uphold and defend the UN Charter and refrain from use of the veto except in rare extraordinary situations to ensure the council remains credible and effective”.
