News analysis In Syria, a war that never ended is tearing the country apart

New bloodbath involves groups sponsored by foreign powers and radical Islamists

- Jonathan Eyal

LONDON - The US and its European allies have called for "de-escalation" in Syria after Islamic fighters conquered significant parts of the country's north, threatening to topple Syrian President Bashar al-Assad's regime.

In a joint statement released on Dec 2 as an appeal for protecting civilians and infrastructure, the US, Britain, France and Germany claimed that the current fighting "only underscores the urgent need for a Syrian-led political solution to the conflict", in line with UN resolutions dating back to 2015.

But such calls for restraint, echoed by many Arab governments, are guaranteed to fall on deaf ears.

The latest dramatic developments in Syria, and particularly the fall of Aleppo, Syria's biggest city, to anti-government forces, are fuelled by a much bigger struggle for mastery in the Middle East.

Syria has been in turmoil since March 2011 when, as part of a broader Middle East movement that came to be called the "Arab Spring", mass demonstrations erupted across the country against the government of Mr Assad, whose family has ruled the nation for more than half a century.

But while similar opposition movements swiftly overthrew rulers in Tunisia, Libya and Egypt, Mr Assad succeeded in clinging to power with the help of Iran and Russia.

Iran has an interest in propping up the Syrian regime because the Assad family belongs to Syria's Shi'ite minority and therefore shares Iran's strand of Islam, but also because Mr Assad allowed his country to act as a conduit for Iranian deliveries of weapons to Hezbollah, the Shi'ite militia in Lebanon, once regarded as Israel's most potent enemy.

And Russia supported Mr Assad because the Russian navy was keen to retain its Cold War-era bases on Syria's shores, within range of a strategic portion of the Mediterranean Sea.