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Air strikes on airports in Syria on Sunday, the third this month, illustrate the multiple fronts in play since Israel launched a war in Gaza, and Israeli determination to counter Iran's ability to wage a multipronged war, political and military observers said.
The “Israeli aggression” against the Damascus and Aleppo airports forced both facilities to stop operating, Syrian state TV reported.
The Syrian meteorological bureau said two of its workers were killed in the strike at Damascus airport.
Both airports were forced to suspend operations after simultaneous strikes on October 12, days after Israel began bombing Gaza in retaliation for a deadly attack by Hamas, the Iran-backed militant group that rules Palestinian territory.
An array of militant groups supported by Iran operate in Syria, having multiplied after the 2011 revolt against President Bashar Al Assad.
Areas under the control of Mr Al Assad are widely seen as a key part of a weapons supply route from Iran to its militia allies in Syria and Lebanon, who have been striking at Israeli targets.
Among them is the Lebanese Shiite group Hezbollah, and co-religionists from Iraq, as well as the Palestinian Islamic Jihad, the main partner of Hamas in Gaza.
Pro-Iranian armed groups have been sporadically firing rockets at Israeli targets from Syrian areas bordering the occupied Golan Heights, and more regularly from Hezbollah strongholds in south Lebanon against northern Israel.
The strikes on Syrian airports show increased “interaction” between Israel's Gaza's offensive and other theatres, Syrian political commentator Wael Alwan said from Istanbul.
“The basic front is in Gaza but there are other fronts in Syria, Lebanon and even Yemen,” said Mr Alwan, a researcher at the anti-Assad Jusoor information centre.
“These fronts are interacting,” Mr Alwan said. “Damascus and Aleppo are de facto Iranian airports. Israel will keep striking to stop them from serving its enemies.”
But Israel's mission has become more complicated because of a deterioration in ties with Russia, which controls the airspace around the Damascus and Aleppo airports, he said.
The two facilities are among the most well-defended positions in areas controlled by the Syrian President.
But last year, the New York Times reported that Russia had removed a major anti-aircraft system from Syria to bolster its campaign in Ukraine, potentially reducing the capacity in Syria to deter Israeli strikes
In the attacks on Sunday, Israel employed air-to-surface missiles fired from the occupied Golan Heights and from the Mediterranean, a Syrian military official said.
A member of the Syrian opposition to Mr Al Assad said the Damascus airport was used mainly to supply Hezbollah in Lebanon, while the Aleppo airport mainly supplied allied militias in northern areas near the border with Turkey. This is in addition to land routes from Iraq that pass near the US zones of influence in eastern Syria.
He said Israel used to inform Moscow in advance of strikes in Syria that passed through Russian-controlled air space, to reduce the risk of harm to Russian forces and as part of wider arrangements between the two countries in Syria.
“We're not so sure that the Israelis have continued to do that in the last two weeks,” said the opposition figure, who specialises in reconnaissance and did not want to be named.
Ties between Moscow and Tel Aviv have soured after Russia, together with China, criticised the Israeli offensive on Gaza.
The ties have been marred by the war in Ukraine and differences over Syria. Russia has caused Israeli concern over its management of Syria by providing air cover for pro-Iranian militias in their capture of areas near Israel.
Moscow had also deepened its ties with the Syrian military after it intervened in the civil war on the side the president in 2015. The war started in 2011, after the authorities used force to suppress a peaceful protest movement against Mr Al Assad's rule.