Ukraine's Foreign Minister Dmytro Kuleba and other Ukrainian representatives prepare to leave as Russian Ambassador to the UN Vasily Nebenzya takes the podium during a meeting of the U.N. General Assembly on the situation between Russia and Ukraine, at th
Ukraine's Foreign Minister Dmytro Kuleba and other Ukrainian representatives prepare to leave as Russian Ambassador to the UN Vasily Nebenzya takes the podium during a meeting of the U.N. General Assembly on the situation between Russia and Ukraine, at the United Nations Headquarters in Manhattan, New York City, U. Reuters / CARLO ALLEGRI

Ukraine appealed to the U.N. General Assembly on Wednesday to stop Russia's "aggressive plans," as U.N. Secretary-General Antonio Guterres warned the 193-member body that an expanded conflict "could see a scale and severity of need unseen for many years."

The General Assembly met for its annual meeting on Ukraine, which coincides with escalating tensions over U.S. accusations that Russia has deployed more than 150,000 troops near Ukraine's borders and is ready to invade. Russia has denied it wants to invade Ukraine and accuses Washington and allies of hysteria.

"No one will be able to sit out this crisis if President Putin decides that he can move forward," Ukraine's Foreign Minister Dmytro Kuleba said. "Active diplomacy, strong political messages, tough economic sanctions and strengthening Ukraine can still force Moscow to abandon aggressive plans."

Washington and allies imposed the sanctions after Russia recognized breakaway regions in eastern Ukraine as independent and ordered Russian troops there to "keep the peace." Washington has dismissed that justification to deploy troops as "nonsense," and Guterres said they would not be "peacekeepers."

Guterres on Wednesday called for a ceasefire and return to the dialogue.

Britain's minister of state for South Asia and the Commonwealth, Tariq Ahmad, urged other countries to also sanction Russia: "The Kremlin must understand the strength of the world's condemnation of President Putin's war of choice."

The General Assembly meeting offers countries a chance to air their views, a move the United States and others hope will show that Russia is internationally isolated over its moves on Ukraine. The body will not take any action on Wednesday.

In 2014, the General Assembly adopted a resolution -- with 100 votes in favor -- declaring invalid a referendum on the status of Crimea, which Russia annexed. General Assembly resolutions carry political weight but are not legally binding.

"We need to close ranks and strongly reject such action," Germany's Minister of State Tobias Lindner told the General Assembly on Wednesday. "If not, then what has hit Ukraine today could happen to other U.N. member states tomorrow,"