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Six years ago, Russia to bolster the Assad regime and helped push rebel forces back to the .

As the second international power to provide substantial support to the Syrian regime, Moscow has been critical to Assad’sÌýmilitary successes since 2015, with Russian airstrikes decimating rebel logistics chains, as well as .

Directing a war between two ideologically divergent powersÌýwas no easy task but tolerable soÌýlong as both sides stuck to the simple equation - Iran took care of the manpower, while Russia provided air support.

With fighting in SyriaÌýnow greatly reduced, the opportunities for conflict between the two sides have never been greater, withÌýa scramble for scant resources and infrastructure in Syria. Assad, meanwhile, has managed to entrench his own power byÌýplaying eachÌýside off one another, analysts say.Ìý

"They both agreeÌýAssad should stay in power, but strategically and ideologically they are not on the same page"

Divisions

Broadly speaking,Ìýregime areas have been divided into two spheres of influence - Iran’s presence in the resource-rich east, while Russia has carved out more strategically important positions on the Mediterranean coast such as Tartous Port and Hmeimim airbase in Latakia.Ìý

It is hereÌýwhere there are signs of growing disagreement between the two major alliesÌýafter Iran sought aÌý, just a few kilometres from a major Russian airbase.

"There have been strong objections from Russia over Iran taking over some key economic interests in Syria, for example, the Port of Latakia. From what we know it was actually Russia that opposed granting these investment rights to Iran,"ÌýKaram Shaar,ÌýResearch Director at the Operations and Policy Center,Ìýtold °®Âþµº.

Israeli in December, said to have targeted an Iranian weapons shipment at the facility, underlined the potential for frictions between Tehran and Russia.

They wereÌýreportedly timed as a Russian plane was landing nearby with suggestionsÌýthat Russia ordered Syrian air defences to stand down duringÌýthe attack.Ìý

If this happened, it is possible the measure was to avoid a repeat episode of the by Syrian forcesÌýbut would show that Moscow hadÌýprior knowledge of the attack, likely owing to its strong ties with Israel.

Syrian air defences'Ìýinability or unwillingness to engage during Israeli airstrikes on Iranian positions indicates a pecking order in Moscow's international priorities, with Israeli relations being a clear priority for Vladimir Putin.

"I think it is reasonable to assume that Israeli attacks against Iranian interests in Syria, and most recently in the Port of Latakia, are actually happening with the full knowledge of Russia,"Ìýsaid Shaar.

"This is evident in that Russia does notÌýallow Syrian air defence systems to be actually used against those attacks."

Russia - backed by the regime's intelligence - also strongly opposed Iranian attempts to obtain the license for the third telecommunications operator in Syria, Shaar said, and has actively sought to reduce Iran’s presence in southern Syria, withÌýthe approval of Israel.

Tensions

Assad has proved adept at playing bothÌýof his allies during the interventions, giving his regime a level of independence from both Moscow and Tehran.

"Much of the coordination in Syria between Russia and Iran actually still happens through the Syrian regime. This is partly because the leverage Russia and Iran have over Syria's president is, while strong, tends to be exaggerated especially in opposition circles," said Shaar.

"They tend to portray Bashar Al-Assad as a mere puppet in the hands of Russia and Iran and I think he is more than that, he is a master of deception."

Russia has recently eased its pressure on the regime over constitutional talks when they realised Assad would not make concessions and instead asked the opposition to limit their demands, Shaar said.

Russia has also a different approach to dealing with Assad. While Tehran operates surreptitiously on a local level in Syria, Russia insists on dealing with Assad directly making Moscow appear a more trustworthy ally forÌýthe regime.

While Russian and Iranian commanders have worked closely in military campaigns throughout the war, Bente Scheller, Head of Middle East Division, Heinrich Boell Foundation, said there is also a level of mistrust between the two sides on a political level.

"They have been sharing duties - in terms of the military action needed to preserve Assad - but there areÌýfew big points of agreement. They both agreeÌýAssad should stay in power but strategically and ideologically they are not on the same page," said Scheller.

"They have very different visions of how Syria should look after the war… but for now so long as they can make sure Assad stays in power, and they can secure their own particular interests, they don't care what vision the other might have."

"With fighting in SyriaÌýnow greatly reduced, the opportunities for conflict between the two sides have never been greater, withÌýa scramble for scant resources and infrastructure"

Territorial ambitions

While Russia has been happy for Iran to provide the in the war, it is also guarded about Tehran encroaching on its interests.

"Russia is territorial about it; they will not allow Iran to have the same benefits because they do not want Iran to have a bigger military presence or control more strategically important points in Syria. For Russia, these benefits are not essential but they will take them when they can and prevent Iran from doing so," Scheller said.

"While Russia wants to withdraw from Syria as soon as it can, Iran wants to remain there and control Syria because they need it as a way into Lebanon and for other regional interests."

Scheller says that the continued Israeli airstrikes on Iranian positions in Syria areÌýevidence that Russia'sÌýmilitary cooperation with Tehran has its limits.

"Russia could control Syrian airspace and it prefers not to. They allow the airstrikes to continue because they would like to rein in Iranian influence and they like a third party -Ìýin this case Israel - doing it for them," Scheller said.

"I don't see Russia treating Iran much differently to how it does Turkey, which is on the other side in the conflict and which Russia has had confrontations within Syria."

Despite Iran pouring in considerably Ìýto help the regime, Scheller believes Russia has been the clear winner in this rivalry.Ìý

"With all the economic opportunities Russia been benefited from, we can say that it'sÌýhad the best share of things in Syria, such as telecoms, the military sector and natural resources. It definitely makes sure it is being served before Iran, and Iran gets what is left over," said Scheller.

Frustrations

For Assad, this rivalry has given him enough breathing space to limit the influence of Iran and Russia on his regime, despite the critical support both sides have provided him during the war.

Dan Wilkofsky, a research analyst with a focus on Syria, said that despite Syrian-Russian relations remainingÌýstable over the past few years,ÌýMoscow has issues with Assad.

"Moscow appears to be frustrated with Assad for his unwillingness to even pretend to play along with a , as well as his other maximalist stances," he said.

"But given all that Russia has gained from its alliance with the Syrian regime, and all it stands to gain if Assad retakes the entire country, it is inconceivable to me that Moscow will fundamentally change its position towards Assad.

"Moscow will likely keep prodding the Syrian president to show more flexibility, but it will continue to support him militarily and politically and insist on his legitimacy."

Paul McLoughlin is a senior news editor at °®Âþµº.Ìý

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