Ukraine's United Nations (UN) ambassador on Wednesday urged all nations that stand against Russia's war against his country to vote for a UN resolution on the humanitarian consequences of its aggression, saying this will send a powerful message aimed at helping people caught in the conflict and ending Moscow's military action.

Russia's UN envoy countered that the emergency special session of the UN General Assembly, which is considering the resolution, is just another political anti-Russian show, set this time in an allegedly humanitarian context. He urged the assembly's 193 member nations to vote against the Ukrainian-backed measure and support a rival South African draft resolution that focuses solely on humanitarian issues with no political assessment.

Ukraine's Sergiy Kyslytsya and Russias Vassily Nebenzia were among the first of nearly 70 national representatives scheduled to speak before the assembly votes on the rival resolutions on the humanitarian impact of the war, which will mark its one-month anniversary on Thursday.

Russia has also called for a vote later on Wednesday in the UN Security Council on its own humanitarian resolution, which has been widely criticised for not referring to its invasion of Ukraine.

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Kyslytsya said the Ukraine-backed assembly resolution, drafted by two dozen diplomats from all parts of the world and co-sponsored by nearly 100 countries, focuses on the need to alleviate suffering and for “immediate cessation of hostilities by the Russian Federation".

"The intention of the initiators and co-sponsors of the draft resolution is to ensure the words are translated into prompt actions on the ground,” he said. "It will be critical to prevent the spillover effect for the entire world”, which is why the text mentions the conflict's impact on food and energy security, especially for least-developed countries.

Nebenzia warned that the adoption of the draft will make a resolution to the situation in Ukraine more difficult.

That's because it will likely embolden Ukrainian negotiators and nudge them to maintain the current unrealistic position, which is not related to the situation on the ground, nor to the need to tackle the root causes of Russia's military action, he said.

Russia had cancelled a Security Council vote on its humanitarian resolution last Friday.

Diplomats had predicted it would be overwhelmingly defeated, with many abstentions and very few yes votes when at least nine are needed for approval along with no vetoes.

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Russia's deputy UN ambassador, Dmitry Polyansky, told reporters on Tuesday that Russia had now asked for a vote Wednesday.

If Western nations dont support the Russian resolution, he said, it will be a reflection of their hypocrisy and refusal to support a purely humanitarian measure without any politicisation, just like other humanitarian resolutions adopted by the 15-member council.

US Ambassador Linda Thomas-Greenfield countered that "Russia cancelled Fridays vote on its resolution because they knew that they didn't have support for that resolution.” She said there still is no support.

France and Mexico decided to take their humanitarian resolution, backed by Ukraine, to the 193-member General Assembly after Russia made clear after two weeks of negotiations in the Security Council that it would veto their draft. It makes clear the aid crisis is a result of Russia's invasion of Ukraine.

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South Africa on Monday circulated a rival draft resolution that is similar to the Russian text before the Security Council and makes no mention of Russia's aggression. It was sent to the General Assembly on Tuesday.

The South African draft calls for an immediate cessation of hostilities as a first step in ameliorating the deteriorating humanitarian situation and encourages political dialogue, negotiations, mediation and other peaceful means aimed at achieving lasting peace.

Unlike Security Council resolutions, General Assembly resolutions are not legally binding, but there are no vetoes and they do have clout in reflecting international opinion.

The US ambassador said supporters of the French-Mexican resolution hoped to get the same vote for the draft as for a resolution adopted by the assembly on March 2 that demanded an immediate halt to Russia's military action in Ukraine and withdrawal of all its forces. That resolution passed 141-5, with 35 abstentions, and was hailed by supporters as a demonstration of Russia's global isolation.

"Russia is the aggressor here and it is absolutely unconscionable for Russia to think that they can put forward a humanitarian resolution," Thomas-Greenfield said. "What Russia needs to do is stop fighting. It needs to stop killing Ukrainians. It needs to stop attacking civilians and forcing people from their homes and creating a humanitarian crisis."

The French-Mexican draft resolution reiterates the March 2 demand for Russia to immediately stop its military offensive in Ukraine and withdraw all its troops, and it demands protection for all civilians and infrastructure indispensable to their survival.

The draft deplores the dire humanitarian consequences of Russia's aggression against Ukraine which it says are on a scale that the international community has not seen in Europe in decades. And it deplores Russia's shelling, airstrikes and besiegement of densely populated cities, particularly the southern city of Mariupol.

Read: Ukraine says situation in besieged Mariupol is 'very difficult'

The proposed resolution strongly condemns attacks directed at civilians and civilian objects, including evacuation convoys, and demands that all parties protect civilians fleeing armed conflict and violence. It further demands unhindered access for aid workers, including their transport, supplies and equipment.

Russia's proposed humanitarian resolution, circulated a day after France and Mexico announced they would take their draft to the General Assembly, doesn't refer to the war at all. It just calls for the protection of civilians in vulnerable situations and safe passage for humanitarian aid and people seeking to leave Ukraine.

It endorses UN Secretary-General Antonio Guterres' call for dialogue and negotiations and urges a negotiated cease-fire to rapidly evacuate all civilians.

Russia's draft further says there is a need for the parties concerned to agree on humanitarian pauses to this end, while never identifying the parties concerned.

Russian authorities maintain they did not start the war and have repeatedly and falsely decried reports of Russian military setbacks or civilian deaths in Ukraine as fake news. State media outlets and government officials insist Russian troops target only military facilities.