More than just 'sound and fury': Anger over Russian 'war crimes' in Syria is reaching a tipping point

The US and Russia exchanged diplomatic jabs on Sunday night and into Monday over the Russia-backed Syrian government's latest scorched-earth offensive on rebel holdouts in the country's largest city.

"What Russia is sponsoring and doing is not counter terrorism, it is barbarism," US Ambassador to the United Nations, Samantha Power, told member nations at a UN Security Council meeting on Sunday.

"Instead of pursuing peace, Russia and Assad make war. Instead of helping get lifesaving aid to civilians, Russia and Assad are bombing the humanitarian convoys, hospitals, and first responders who are trying desperately to keep people alive."

Hundreds of people have died over the past week in the worst aerial bombardments on the rebel-held eastern half of Aleppo since the war began in 2011. The bombings punctuated the collapse of a fragile ceasefire brokered between the US and Russia earlier this month.

The UN's special envoy for Syria, Staffan de Mistura, noted on Sunday that the bombardments had reached a "remarkable new intensity - unprecedented in scale and type of bombing," and warned that a renewed takeover battle for rebel-held eastern Aleppo could mean "a slow, grinding, street-by-street fight, over the course of months, if not years."

The Syrian Civil Defense, also known as the White Helmets - local rescue teams who help dig people out of the rubble of airstrikes - reported "horrific indiscriminate bombardment" and "nonstop airstrikes" on Saturday morning.

"Our teams are under tremendous pressure," the group tweeted.

The rescue service also says they have been targeted by Syrian and Russian warplanes continuously - most notably last week, when they say they were attacked while trying to help UN aid convoys that had been bombarded while trying to deliver supplies across the Turkish-Syrian border.

White Helmets buildings in Aleppo were also deliberately targeted in multiple airstrikes on Friday, Abdul Rahman al-Hassani, the chief liaison officer for the White Helmets, based in Aleppo, told The Daily Beast.

Britain's ambassador to the UN, Matthew Rycroft, walked out of the Security Council meeting on Sunday as Syria's envoy to the UN, Bashar Jaafari, began to speak. The US and France also walked out.

"It is difficult to deny that Russia is partnering with the Syrian regime to carry out war crimes," Rycroft said.

Britain's newly appointed foreign secretary, Boris Johnson, joined in the chorus of international condemnation shortly afterward, telling the BBC's Andrew Marr Show that Russia was "guilty of protracting" the war in Syria and of "making it far more hideous."

More than just 'sound and fury'

Echoing the regime, Russia once again defended itself by insisting the airstrikes were targeting Syria's militants.

"In Syria hundreds of armed groups are being armed, the territory of the country is being bombed indiscriminately and bringing a peace is almost an impossible task now because of this," Russia's Ambassador to the UN, Vitaly Churkin, told the council.

The Kremlin's spokesman, Dmitry Peskov, called the US and UK envoys' language "unacceptable."

"We note that the tone and rhetoric used by official representatives from the UK and US is generally unacceptable and it can seriously damage the settlement process and our bilateral relations," he told reporters on Monday.

Jeff White, a military expert at the Washington Institute for Near East Policy, said that the jabs are, at this point, more than just "sound and fury."

Europe analyst Alex Kokcharov, a risk analyst with IHS, said the language was "probably the strongest we've heard since the Cold War ended."

"This is significant - both the fact that the U.N. Security Council met on a weekend and also that they have used words such as war crimes," Kokcharov told NBC News.

White noted that while the Obama administration is "not going to make a major policy change at this point, it may be willing to increase clandestine support to the rebels somewhat."

Any concerted effort by the administration to end the bombardments remains elusive, however. Obama barely mentioned the war in his final address to the UN General Assembly last Tuesday, re-iterating his long-held belief that "there is no ultimate military victory to be won." And he has resisted calls from both sides of the aisle to pass sanctions on the Assad regime and its supporters.

The verbal crossfire at the UN circumscribes how much diplomatic progress US Secretary of State John Kerry will be able to make with his Russian counterpart, Sergei Lavrov, on halting the indiscriminate bombing campaign.

"Hard to see how this can go forward now with any credibility," White said.

A dramatic setback

The new scorched-earth campaign is a dramatic setback for the opposition in Aleppo, which had been on the verge of breaking a month-long government seige on the city early last month in "one of the largest coordinated rebel campaigns of the war to date."

The ceasefire put a temporary end to the heavy fighting - but it also appears to have swung the pendulum back in the regime's favor.

Hadi Alabdallah, a Syrian journalist on the Aleppo frontlines, told Business Insider at the time that "the regime-allied forces deteriorated very quickly" in the face of the rebel assault.

"It was very surprising, and much faster than anyone had expected," he said. "Officers from those [pro-regime] militias fled and left their soldiers out on the field, so they started to flee as well. That's why the artillery academy was so easy to overrun - it was captured within two hours."

Less than three weeks into the ceasefire, however, the regime unleashed its most ferocious assault on the city to date - and with US-Russian relations rapidly deteriorating, a negotiated pause in the bombardments appears unlikely.

"The Assad regime and with direct participation of its ally Russia and Iranian militias has escalated its criminal and vicious attack on our people in Aleppo employing a scorched earth policy to destroy the city and uproot its people," read a statement signed by 30 mainstream rebel groups released on Sunday.

One hundred people died in the bombings on Friday alone, according to James Le Mesurier, head of Mayday Rescue, which trains Syrian rescue workers. Nearly two million people in both the rebel-held and government-held areas of Aleppo were left without water.

It was "the worst day that we've had for a very long time," Le Mesurier told the New York Times' Ben Hubbard. "They are calling it Dresden-esque."