Syria Insight: Why did Russia allow Israel to bomb Damascus Airport?
While Israel has launched countless attacks on Iranian arms convoys in and around the airport before, the damage to the civilian annex was unprecedented.
Syrian authorities say the runway could be closed to civilian traffic for months, as the UN warned humanitarian access to regime areas will be hindered for some time due to the damage.
Israel has long argued that Damascus Airport is a den of Iranian weapons and troops smuggling and the US and several European countries have already sanctioned private Iranian carrier Mahan Air for that reason.
This, and a land bridge via Iraq, has given Tehran a direct link to Iranian Revolutionary Guards Corps (IRGC) militias in Syria and Hezbollah in Lebanon - a key concern for Israel.
Damascus Airport has served as an entry point for Iranian pilgrims visiting Shia holy sites in Syria as well as being a vital component of Iran's military axis, according to Arash Azizi, author of The Shadow Commander: Soleimani, the US, and Iran's Global Ambitions.
"As the Iranian intervention in Syria expanded, the IRGC was able to use even the civilian traffic for military purposes, contravening norms and rules and disgruntling many, even inside Iran's own civil aviation sector,” Azizi told The New Arab.
"Qassem Soleimani would personally use flights by Mahan Air, an airline based in his home province of Kerman, to transfer men and equipment between Tehran and Damascus. There are open testimonies about this from Iran's own officials."
But Israel's targeting of a civilian site would appear to overstep an unofficial coordination agreement with Russia on airstrikes in Syria, which have been primarily focused on Iranian and Hezbollah weapons convoys and militia bases.
The launch of Russian S-300 anti-aircraft missiles last month during Israeli airstrikes highlighted some disgruntlement in Moscow at Israel's stance on the Ukraine conflict yet there is little to indicate a breakdown in cooperation.
Reports including in pro-Iranian media suggest that Russia was notified by Israel before the attack on Damascus Airport and air defences were not activated.
Israel is likely aware that Russia is entirely focused on the war in Ukraine to risk further destabilisation in Syria, where Moscow operates an airbase, port, and other military outposts.
"Israel’s bombing of Damascus Airport along with [Israel Prime Minister Naftali] Bennet’s open threats against Iran point to an unprecedented escalation," Azizi added.
"In more ordinary times, Russia would object to the targeting of civilian infrastructure as this goes beyond the tacit agreement Moscow and Tel Aviv had. But Moscow is now too engulfed with Ukraine to make a stand on this question."
Iran has invested huge sums of money and manpower to keep Assad afloat and his continued survival and growing acceptance from Arab states show that the gamble has paid off, Azizi said.
Yet Tehran remains bogged down with domestic issues such as its violent crackdown on protests, apparent security failures after the assassination of Iranian scientists, and the danger of Tehran losing its market share to Russia in the Asian oil market.
"Can the regime go to war to deflect attention from all this? I don't think so. The regime has shown that it is quite patient and averse to open and direct intervention against Israel. [Ayatollah Ali] Khamenei is quite a prudent and conservative leader...and is unlikely to head into a suicidal confrontation with Israel," Azizi explained.
"As for intervention in Syria, it will indeed continue for as long as the regime can, although it is possible that it will draw it down based on possible agreements with countries of the region."
Despite this, Omar Abu Layla, CEO of the DeirEzzor24 monitoring site, said Iran has continued to bolster its forces in Syria and increased smuggling and the drugs trade in the east - by many accounts a key source of revenue for Tehran and its proxies.
"The recent airstrikes indicate that all Iranian moves in Syria are under international monitoring," he said.
"However, I personally do not see them useful for several reasons, most notably because these strikes are intermittent and not continuous. This means Iranian militias can regain their influence even more after the bombings."
Russia's presence in Syria was seen by many regional powers - including Israel - as a useful counterweight to Tehran’s influence in the area.
These powers are likely comfortable with Israeli strikes on Iranian targets, so long as they don't threaten the Assad regime's hold on power.
Gregory Waters, Analyst at the Counter Extremism Project and fellow at the Middle East Institute, said there are no signs that reports of major Russian troop withdrawals and Iranian fighters replacing them are correct, despite the obvious ratcheting up of Israel's air campaign.
"It's important to remember that several years ago the Russians drew down a lot of their forces in Syria, shifting from doing direct on-the-ground combat support to more training, commanding, advising logistical, and air support," he said.
"So, when we talk about if and why Russians would withdraw from Syria now, the first question had to be: what would they actually withdraw? The only things that could be useful in Ukraine that are still in Syria are airframes, and if some of these were shifted over to Ukraine that's not a gap that Iran steps in to fill."
Bente Scheller, Head of Middle East Division, Heinrich Boell Foundation, agreed there are no signs of Russian troop movements from Syria to Ukraine, but Iranian militias have taken over some checkpoints in southern Syria - a red line for Israel.
"Israel would prefer not to have any Iranian-linked fighters close to its borders, so the partial Russian withdrawal that we are seeing is not in its interest. That means there will be more Russian airstrikes in Syria in the future," Scheller said.
"For Moscow, [its relationship with] Syria has been useful in many ways but it is clearly not important enough for Russia to protect it from attacks of others. We can see this in the north, but also in the hundreds of Israel airstrikes in Syria since 2011."
Scheller said that Moscow's preoccupation with the war in Ukraine poses other problems for the Syrian regime, beyond doing little to reduce Israeli airstrikes.
This includes a possible new offensive by Turkey in northern Syria, and growing tensions between Syrians living in regime areas and Iranian-backed militias, notorious for their cronyism, brutality, and missionary tendencies.
"On top of that, wheat shortages and increasing prices as a consequence of the war in Ukraine hit Syria's population hard, since before that 90 percent of the population lived in poverty already," said Scheller.
"The regime cannot really hope to obtain more support from either Russia or Iran in this situation, and after Moscow came under international sanctions it is also not that useful any longer for sanctions evasion."
With Israeli strikes decimating one of Syria’s main transport hubs, the effects on the civilian population and business could become more pronounced in the coming weeks and months.
"It is surprising that the regime has not been more vocal in condemning these strikes - possibly this is because there was more to the strikes and the regime does not want to draw more attention to it," Scheller added.
Paul McLoughlin is a senior news editor at The New Arab.
Follow him on Twitter: @PaullMcLoughlin