The Defense Department made a big gaffe that helps Putin and Assad in Syria

The spokesman for the US military operation against the Islamic State made a comment in a Wednesday press briefing in Baghdad that helps justify Russia's continued attacks on Syria's largest city in the midst of a truce.

US Army Col. Steve Warren, the spokesman for Operation Inherent Resolve in Iraq, was asked whether Russian airstrikes on Aleppo, the current epicenter of the war, meant that Moscow was preparing to end the cessation of hostilities (CoH) agreement between government forces and the opposition signed on February 29.

Warren responded that it was "complicated" because Nusra "holds Aleppo" and is not party to the agreement.

"I'm not going to predict what their intentions are," Warren said of Russia. "What I do know is that we have seen, you know, regime forces with some Russian support as well begin to mass and concentrate combat power around Aleppo. ... That said, it's primarily al-Nusra who holds Aleppo, and of course, al-Nusra is not part of the cessation of hostilities.  So it's complicated."

As Middle East analyst Kyle Orton noted on Twitter, Warren came "pretty close" to saying the coalition supports Russia's airstrikes in the city. Those strikes, however, are aimed at degrading any and all opposition to Bashar al-Assad - the embattled president of Syria who the Obama administration has repeatedly insisted "has to go."

Warren, moreover, was effectively echoing Russia's own military spokesman, Lt. Gen. Sergei Rudskoi. He said earlier this month that 8,000 Nusra militants were amassing around Aleppo and preparing to cut off the city's main road to Syria's capital, Damascus. 

Emile Hokayem, an expert on Syria and Middle East analyst at the International Institute for Strategic Studies, seemed surprise by Warren's comments.

"Does the US military really believe that Nusra 'holds Aleppo'?" Hokayem tweeted on Friday. "Did Warren misspeak?"

While Nusra has indeed been building up its presence in Aleppo since February, the city is also occupied by civilians and armed opposition groups associated with the US-backed Free Syrian Army that agreed to abide by the fragile agreement. 

The CoH was brokered by US Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov at Geneva in February. Lavrov indicated that Russia would continue supporting the Assad regime's attempts to "liberate" Aleppo, which he said had been "captured by illegal insurgent groups."

But for one of the US' top military leaders to stop short of condemning Russia's airstrikes on the city sends mixed signals about Washington's commitment to upholding the truce. Warren's comments came two days after US President Barack Obama urged Russian President Vladimir Putin to "use his influence with the Assad regime to live up to the commitments that they've made in the context of the cessation of hostilities," said Josh Earnest, the White House press secretary.

He added: "Unfortunately, we've seen that the cessation of hostilities continues to be fragile and increasingly threatened due to continued violations by the regime."

'The worst day in Syria for over a year'

Syria's civil defense, a neutral organization of nearly 3,000 volunteers that respond to bombings against civilian communities in Syria, said warplanes attacked Aleppo at least 20 times on Friday in what was "the worst day in Syria for over a year." At least 14 people were killed in the attack and dozens more wounded. 

In Idlib, meanwhile, the White Helmets recorded even more attacks than in Aleppo on Friday. Nusra took over bases and seized US-supplied weapons from the Free Syrian Army's 13th Division in Idlib last month, giving Assad another bargaining chip to argue that he is the best option for preventing the spread of terrorism in Syria.

Significantly, Nusra's takeover of rebel-held areas around Syria has been met with fierce backlash by activists and the more moderate rebel groups battling Assad's forces. Opposition groups realize that "the more territory al-Nusra controls, the more the 'us or them' narrative grows stronger and, ironically, the less support moderates get from the coalition," Abu Faisal, a Syrian aid worker who goes by a pseudonym, told Business Insider's Pamela Engel last month.

But Nusra's presence in Idlib and Aleppo - and, now, Warren's hint that the US might not be wholly opposed to a Russian offensive there - has given Moscow an excuse to revamp its military presence inside Syria just over one month after announcing it planned to withdraw from the conflict. 

The Wall Street Journal reported earlier this week that Russia is moving heavy artillery back into the northeast, likely in preparation for a major escalation there.

"If Russia is signaling an offensive against Nusra, you can be sure other rebel groups will be targeted," Nadav Pollak, a senior fellow at the Washington Institute, tweeted last week.

And as Jeff White, a military analyst at the Washington Institute for Near East Policy, told Business Insider in an email, the Russians are likely taking advantage of the crumbling cessation of hostilities by blaming violations on Nusra - and everyone else who opposes Assad.

"Even if they don't participate in a 'pitched battle' for Aleppo," White said, "the Russians can still help the regime complete the isolation of the city."