New Zealand has demanded that Syria stop the bombing its own civilians - telling the U.N. Security Council Russia's support of the Assad regime is "destroying innocent lives".
The strong condemnation was made at an emergency meeting called to discuss worsening violence in Syria and as government planes bomb the city of Aleppo.
And it comes as Prime Minister John Key says Russian president Vladimir Putin's ego is driving much of his country's policy on the conflict.
The United States has accused Russia of "barbarism", and British Foreign Secretary Boris Johnson said it may have committed war crimes.
A ceasefire between the Syrian Government and rebel forces collapsed last week when an aid convoy was bombed.
Fighting has since intensified in Aleppo, where more than 250,000 civilians are trapped.
The Syrian airforce push to capture the rebel-controlled areas of the city has Russian and Iranian support and there are reports of thousands of civilian casualties.
New Zealand's Acting Ambassador Carolyn Schwalger chaired the Security Council emergency meeting and told members New Zealand "demands that the Syrian Government immediately cease its bombing of civilians and demonstrate genuine commitment to achieving a negotiated peace".
All countries but particularly those with most influence over the Syrian Government should do the same, Schwalger said in the unusually blunt statement.
"I speak in particular to those whose political and material support is making the Syrian Government's current actions possible.
"Your support is undermining any remaining prospects for the peace process. And it is destroying innocent lives under the guise of countering terrorism."
Syria needed to ground its planes and hold back its armies.
"New Zealand appeals to the governments of Russia and Iran - if you are serious about peace, do everything in your power in the coming days to halt the fighting and give the US-Russia arrangements a chance."
Russia has blamed the ceasefire breakdown on the rebel forces, including those backed by the West, and says some groups in eastern Aleppo are holding the local population hostage and using them as human shields.
Schwalger said New Zealand recognised that those opposed to the rule of President Bashar al-Assad also had responsibilities, and countries with influence on the opposition needing to encourage respect for the ceasefire and the disassociation with terrorist groups.
"However, what the Syrian Government and its allies are doing is making that disassociation harder and prolonging the war.
"All involved in Syria need to take a hard look at themselves and ask whether they intend to be genuine collaborators in the search for peace."
It is New Zealand's turn to hold the Presidency of the Security Council this month and Prime Minister John Key is back in the country after travelling to New York where he chaired a heated Security Council debate on the Syria crisis.
Schwalger referenced Key's statement, saying Security Council members in response agreed points including that there can be no military solution to the Syrian conflict, and the urgent need to stop the fighting.
"It is therefore with utter dismay that we find ourselves back in this Chamber as Syrian planes, reportedly with Russian support, inflict carnage on eastern Aleppo.
"These actions, reportedly including the use of incendiary and other indiscriminate weapons, are disturbing and demonstrate total disregard for their devastating impact on civilians."
This morning, Key told Newstalk ZB the Syrian crisis was "deeply frustrating".
"You go back to 2010 people were holidaying there. Now you have half the entire population displaced, hundreds of people losing their lives, those scenes you see on your nightly tv screens of beautiful little children dying."
Key said he believed the Russians did want a ceasefire but for different reasons to the West.
"A lot of it comes down to, A, backing their man Assad, B, proving they stand by their man Assad, but maybe the main thing is [Russian president] Vladimir Putin's ego - he wants to say, 'You want to get resolutions to issues, I'm your guy and come to Moscow."
There was "no long-term place for Assad" as Syrian leader, Key said, but there would have to be a transition period if Russia was to support his ousting.
"This is a guy who has used chemical weapons against his own people, amongst everything else. He has to go."
Save the Children has cited reports that about half of recent casualties in Aleppo were children.