Russia's and Syria's massive offensive against rebel-held Aleppo led to one of the most contentious meetings of the U.N. Security Council in years.

The U.S., France, and Great Britain called for an emergency session of the Council after more than 300 people were killed in indiscriminate Russian bombing of Aleppo in the last three days.  During the meeting, Secretary General Ban Ki-moon pleaded with the U.S. and Russia to resurrect a ceasefire before it was too late.  Syria, he said, is "on the brink."

But the session turned acrimonious when both the British foreign minister, Boris Johnson, and U.S. ambassador to the U.N. Samantha Power accused the Russians of war crimes.

Financial Times:

Samantha Power, US ambassador to the UN, said Russian and Syrian forces were “laying waste to what is left of an iconic Middle Eastern city”. Ms Power and her UK and French counterparts later walked out of the session when the Syrian representative addressed the council.

The allegations against Russia, which included claims the Kremlin was condoning war crimes, came as Aleppo was bracing for an onslaught by Russian-backed Syrian government forces.

Following the breakdown of a ceasefire agreement negotiated between Washington and Moscow last week, Aleppo has seen some of the worst aerial bombardment since the war’s outbreak, leaving hundreds dead.

In theory, the US and Russia are still working to see if there is a way to revive the ceasefire plan announced two weeks ago — John Kerry, US secretary of state, has called for military aircraft to be barred from flying over contested areas. However, the fierce exchanges at the UN underlined the collapsing space for diplomacy.

In a blistering speech, Ms Power said: “Instead of pursuing peace, Russia and Assad make war.” While Moscow was likely to argue that it was pursuing terrorists in Syria, she said that “Russia is espousing fiction”. “What Russia is sponsoring and doing is not counterterrorism; it is barbarism,” she added.

Vitaly Churkin, the Russian ambassador to the UN, said that the US had little influence over the rebel groups that it was backing in Syria. “Bringing a peace is almost an impossible task now,” he said.

Sunday’s urgent meeting was held at the request of the UK, the US and France as fighting continued to rage around Aleppo and the rebel-held east of the city suffered a new bombardment, the latest in a spiral of violence that has left the planned ceasefire in tatters. The Syrian Observatory for Human Rights said that at least 26 people had died in the new round of regime airstrikes on the city on Sunday.

Jean-Marc Ayrault, France’s foreign minister, told the meeting that Russia and Iran, which also backs the Syrian regime, would be accomplices to war crimes if they did not press President Bashar al-Assad to stop the violence.

He said the Syrian government “has clearly made the choice of a military escalation”.

Boris Johnson was even more direct than Power:

Ban Ki-moon, the UN Secretary-General, urged the powers to work to “end the nightmare”, singling out Russia’s use of bunker-busting bombs to hit schools and hospitals operating in basements.

“How much longer will all those with influence allow such cruelty to continue?” Mr Ban said. 

Earlier, Boris Johnson, the Foreign Secretary, said Russia may have committed war crimes by bombing a UN aid convoy last week and accused President Putin of not only “handing the revolver” to the Assad regime, but also helping to pull the trigger.

In a display of disgust towards the Assad regime, Matthew Rycroft, the British ambassador to the UN, walked out of a specially convened Security Council meeting when the Syrian ambassador rose to speak.

“Aleppo’s inhabitants… are now facing an unprecedented, unrelenting onslaught of cruelty,” he said.

“In short, it is difficult to deny that Russia is partnering with the Syrian regime to carry out war crimes.”

When the Syrian representative got up to speak, the U.S., French, and British delegations walked out.

This would appear to be a rupture between Russia and the West that won't be easily healed.  I'm sure both Putin and President Assad don't care what the rest of the world is thinking.  They are winning.  The destruction and capture of the last urban stronghold of the rebels will, for all intents and purposes, end the war.  All the rebels will be able to do in the future is harass Assad's forces from the few remaing towns and villages they control.

With the capture of Aleppo, the humilation of President Obama and the U.S. will be complete, and our feckless policy in Syria will be exposed as naive and foolish from the start.