Earlier, the Russian military reached out to the militants in Eastern Ghouta, suggesting they leave the area “in goodwill” — similar to how the militants had been evacuated from Aleppo. According to Moscow , Hayat Tahrir al-Sham and its affiliates “dismissed the proposal and continued to shell [Damascus], holding the civilians of Eastern Ghouta as human shields.”

His statement, if coupled with earlier claims by Russian Foreign Minister Sergey Lavrov, reflects Russia’s view on the issue, in which Moscow has seen attempts to “impose a truce” as part of the bigger plot to topple Assad. Days before the Security Council vote, Lavrov said the truce should not cover all of Syria , and fighting should continue against the Islamic State (IS), Hayat Tahrir al-Sham and "other groups who are shelling residential quarters of Damascus.”

The Russian Foreign Ministry said it is counting on “foreign patrons of anti-government militant groups … to ensure that their charges stop combat activities in the interests of the quickest and safe transit of humanitarian convoys.” Commenting on the Security Council decision, Russia's UN envoy Vasily Nebenzya didn’t mince words, calling on the United States to “ give up its occupation-driven attitude [on Syria].”

Putin’s call came after humanitarian monitors said they suspected forces supporting Syrian President Bashar al-Assad had launched a chlorine attack on the battered city near Damascus. Russia, however, claimed terrorist groups in Eastern Ghouta such as Hayat Tahrir al-Sham had been plotting to use chemical weapons themselves and blaming Assad supporters, according to Russia's state-run Tass news agency .

MOSCOW — After the UN Security Council’s demand Feb. 24 for a cease-fire across Syria proved ineffective, Russian President Vladimir Putin on Feb. 26 called for a five-hour-daily humanitarian pause in fighting in rebel-held Eastern Ghouta beginning Feb. 27.

"Over the last two years, residential areas of Damascus have been regularly shelled from Eastern Ghouta. Every time this happened we called upon the UNSC [Security Council] to voice their assessment of these acts, but our American and European colleagues dodged any response. This raises certain flags,” Lavrov argued.

Recent escalations in Syria, including the US strike on pro-regime forces in Deir ez-Zor — which killed Russian combatants — is raising speculation about potential fallout from Moscow’s strategy in Syria and possible escalation between the Russian and American militaries.

The strike occurred Feb. 7, yet the exact number of Russians killed in the fight with the US-backed Syrian Democratic Forces has ranged in various news sources from 10 to 200 soldiers and mercenaries in Russia’s employ. The number of US airstrikes also has remained as a matter of speculation.

Moscow denied that any Russian servicemen were even in the area, but it has been quiet about whether Russian citizens ultimately got hurt in the attack. Reports of Russian mercenaries, particularly from the well-known private military company Wagner Group, also emerged shortly after the incident and were backed up by personal stories of relatives and friends of alleged Wagner contractors, some of whom supposedly ended up in hospitals in Moscow and St. Petersburg.

Two weeks after the battle in Deir ez-Zor, the Russian Defense Ministry recognized that “several dozen” citizens of Russia and other former Soviet states had been killed or wounded, but the ministry said the fighters had traveled to Syria “of their own accord and for a variety of reasons.”

The fallout for Russia has been remarkable. Given the fast-approaching presidential election March 18, the potential costs of the incident for Putin’s reputation are high; thus, public discussion of the incident has mostly evolved in the framework of “American aggression on the pro-government forces.”

As for the incident’s implications for the US-Russia relationship in Syria, the lack of credible information about the attack gives life to abundant conspiracy theories and speculation. Perhaps this is the type of development where those who know what happened keep silent, as those who speak up don’t necessarily know much. What we do know, however, is the Russian and American militaries were unconventionally in step with each other in playing down the incident and dismissing rumors of a wider war.

The attack sets a new low in the threshold for a direct military collision of the two powers. Yet both Moscow and Washington evidently seek to dodge such an encounter.

Two weeks after the incident in Deir ez-Zor, the Russian ambassador to Washington, Anatoly Antonov, signaled that Russia wasn’t seeking to further confront the United States. Speaking at a reception at the Russian Embassy dedicated to Army Day, Antonov said confrontations between countries and groups of countries don’t benefit anyone.

“Regardless of what anyone has to say, representatives of different states assembled here today are not adversaries, but partners, [and] today international military cooperation is at its highest demand,” he said.

Andrey Sushentsov, program director at the Valdai Discussion Club, told Al-Monitor he believes “deconfliction” has probably been the only working collaborative theme of US-Russia relations in Syria.

“Russia’s highest officials have been calling it ‘the most reliable and trustworthy’ working channel. Therefore, I rule out that the incident [in Deir ez-Zor] was an intentional provocation meant to break the fragile trust. Russia seeks to avoid deterioration of its relations with the US in the theater of war where — besides Russia and America — Turkey, Iran, Israel, [Saudi Arabia] and Qatar have been active players,” Sushentsov said.

Outside of that particular episode, there’s still enough reason to fear that Moscow and Washington might continue testing the flexibility of their respective red lines. America’s key goals at this point seem to involve three things:

To ensure and justify its further presence on the ground under the pretext of fighting the remnants of IS.

To cut Assad off from his oil and gas revenues by seizing Syrian facilities, thus making his standing less sustainable in the long run.

To build political and military deterrents to the spread of Iranian influence in Syria and beyond.

None of this may deliberately seek to counter Russia directly, but it’s clear that implementing at least two of those goals may be bound to a potential clash with Russia. Moscow may not necessarily feel it should burn its political capital by challenging this US administration’s long-term objective of containing Iran. But the US military presence in Syria because of Assad increases pressure on Moscow’s political, financial and military assets. And pro-Assad forces may still be thinking of trying to take control of the oil and gas facilities.

Lavrov said those pushing for adoption of the Security Council cease-fire — which doesn’t include Russia’s conditions to allow fighting to continue against IS and others attacking Damascus from Eastern Ghouta — aren’t doing so because they’re concerned about humanitarian issues. Rather, he said, they want “to shift the focus” from the urgent need to restart the Geneva peace talks. They want to "promote Plan B," implying regime change.

The incident in Deir ez-Zor was yet another indication that things in Syria aren’t going the way Moscow thought they would at the end of 2017. Russia has sought to turn the conflict over to the political realm, including through the Syrian National Dialogue Congress Russia hosted last month in Sochi. Russia started to wind down some of its military presence to put more focus on diplomacy. Now that the military situation is again deteriorating, Russia faces the unpleasant need to reassert its presence and take action to safeguard its political and other assets. Rumors have it that Putin is considering replacing the current commander of the Russian contingent in Syria, Col. Gen. Alexander Zhuravlev, with his predecessor, Col. Gen. Sergey Surovikin, who had served in this position from March to December and now heads Russian aerospace forces.

On Feb. 22, Russia beefed up its military presence in Syria by deploying at Latakia at least two brand-new Su-57 stealth fighters as well as four Su-35s, four Su-25s and one A-50U advanced airborne early warning and control aircraft.

Leonid Nersisyan, a military analyst and chief editor of New Defense Order Strategy magazine, told Al-Monitor that the move may be pursuing two objectives: to potentially contain Turkey now that the Syrian army has entered Afrin, and to beef up the Russian air force while testing the Su-57s.

“The fifth-generation Su-57s have been deployed to undergo combat tests. The Syria campaign may be important for further modification of the aircraft, including its stealth technology. In its current state, however, the Su-57 is likely to be used with great caution and is unlikely to have a big impact on the [Syrian] operations, unlike the rest of the just-deployed jets,” Nersisyan added.

Russian lawmaker Vladimir Gutenev had earlier said that the Su-57 deployment may serve “as a constraining factor for aircraft of neighboring states that periodically violate Syrian airspace.”

The Pentagon reacted to the Su-57 deployment by saying it “poses no threat to the US-led coalition’s military operations and the United States will continue to deconflict operations with Russia as necessary.”

While “deconfliction” today is as needed as ever, the incident in Deir ez-Zor revealed it is neither a silver bullet for preventing military clashes nor a substitute for a broad political agreement. Such an agreement is nowhere to be seen at this point, and the more Syria teeters on the edge of a greater military shake-up, the more the United States and Russia risk polarization.