Syria’s long-running civil war has entered a markedly more dangerous phase as opposition forces capture strategic cities and vital infrastructure. Military analysts and diplomatic sources say these developments, the most significant since a 2020 ceasefire, threaten to destabilise the wider region.

Opposition fighters have seized the major cities of Aleppo and Hama, along with control of Highway 5, a critical artery linking northern and central Syria.

According to Stanislav Ivanov, a senior researcher at Moscow’s Institute of World Economy and International Relations (IMEMO RAS), these gains represent the rebels’ most substantial territorial advances since the March 2020 ceasefire.

“The capture of these strategic points fundamentally alters the balance of power in Syria’s north and central regions,” Ivanov said in a detailed analysis. “The opposition now controls key logistics routes that have long been essential to government forces.”

Despite Ankara’s public assertions of neutrality, evidence suggests substantial Turkish support for the offensive, which began on November 27, including vehicles with Turkish registration plates parking outside Aleppo Castle.

Military experts note that Turkey, since the 2020 ceasefire, has exerted extensive influence in opposition-held areas, providing training, equipment and operational guidance.

“Turkey’s role goes far beyond mere influence,” said a Western diplomatic source in Beirut, speaking on condition of anonymity. “Their strategic direction and material backing have been crucial to the opposition’s recent successes.”

After 13 years of unrelenting conflict, the Syrian army is showing signs of severe depletion and is struggling to mount an effective defence. Its predicament is worsened by the weakening of key allies, notably Lebanese Hezbollah, which has sustained significant losses both at home and from Israeli airstrikes in Syria.

Russian aerospace forces continue to launch strikes against advancing rebel groups but face considerable constraints. “Russian air support is limited by the militants’ tactic of dispersing among civilian populations,” said the Moscow-based military analyst.

“Their proximity to retreating government troops also complicates targeting decisions,” he added. Russia is extremely vulnerable in the current collapse of the control of the main cities of the country, as its base in Tartus would then become a target of any westward movement of HTS troops. Russia’s regional enemies would also like to see Moscow’s naval forces move out.

The changeable battlefield situation has opened opportunities for various regional players. Israel, wary of both Iranian influence and radical Islamist forces, has carried out strikes against Hezbollah and Iranian Revolutionary Guard positions. Although these actions have indirectly aided the rebels, Tel Aviv maintains that its sole aim is to prevent Iran’s further entrenchment in Syria.

Meanwhile, the United States, which supports Kurdish forces east of the Euphrates, has taken advantage of the chaos to target pro-Iranian groups along the Iraq-Syria border. Kurdish forces have also expanded their territory, taking control of the administrative centre of Deir ez-Zor Province.

The human cost of the conflict continues to rise. “Over 1mn Syrians have been killed or disabled, while some 7 to 8mn live as refugees in neighbouring countries,” Ivanov noted. A further 4mn are internally displaced, and about eight million reside in areas outside government control.

Those remaining in government-held territories face dire shortages of food, medicine, and other essentials, further exacerbated by Western sanctions. Healthcare infrastructure has been particularly hard hit, with numerous hospitals and clinics destroyed or rendered inoperative.

International attempts to resolve the crisis remain deadlocked. The Astana peace process, involving Russia, Turkey and Iran, seems increasingly marginal in light of recent developments. Western diplomatic sources say any settlement would likely require the withdrawal of all foreign forces and a UN Security Council-mandated peacekeeping operation.

“Erdogan and his entourage can be considered the main beneficiary of the new outbreak of violence in Syria, while the people of this long-suffering country have become the victims of these events and the generally worsening crisis situation in the SAR,” Ivanov writes.

“The prospects for such coordination appear dim amid intensifying regional rivalries,” said a UN official involved in Syria’s peace efforts. “Wider geopolitical tensions have made forging consensus even more challenging.”

The analyst outlined three potential scenarios: a rebel advance towards Damascus, a military stalemate prompting renewed negotiations, or a prolonged period of fragmented control with no clear resolution.

The eventual outcome will largely depend on whether external powers continue to bolster their respective allies in this complex and evolving conflict.