Syrian government forces are advancing in the northern Aleppo countryside toward al-Bab, raising the specter of a clash with the Turkish military and Ankara-backed Syrian rebels who have for weeks struggled to dislodge the so-called "Islamic State" (IS) from the strategic town.

Fighting in and around al-Bab is some of the most complex in Syria's multi-sided war. To the north, west and east, a Turkish military and allied rebel pincer movement has been slowed by heavy IS resistance, including street battles, snipers and suicide bombings.

Further to the east around Manbij, Turkish-backed forces have also clashed with US-backed Syrian rebels dominated by the Kurdish YPG militia. Ankara considers the YPG a terrorist organization tied to Kurdish rebels in Turkey and has vowed to root out it out of Manbij once al-Bab is captured.

But such a Turkish move against Manbij would be viewed as unwanted by the United States as the Kurdish-Arab rebel force is leading a US-backed offensive against IS in the militants' de facto capital of Raqqa.

Syrian Army closes in on al-Bab

Meanwhile, since restoring government control over all of Aleppo in December, the Syrian army and allied militia have approached to within six kilometers (four miles) of al-Bab to the southwest, advancing along the strategic Aleppo-Al-Bab Highway.

Syria's military command said Thursday the army and allied forces had retaken 32 towns and farms in the past three weeks, reasserting control over 250 square kilometers.

Al-Bab is about 40 kilometers (25 miles) northeast of Aleppo. On the ground, the hollowed out Syrian army is backed by an array of militias, Iranian forces, Iran-backed groups and Hezbollah.

Complicating the battlefield environment, in addition to US efforts against IS, Syria, Russia and Turkey are all carrying out airstrikes against IS targets in and around al-Bab. 

Although Russia backs the Syrian government with airstrikes, its air force has recently also supported Turkish-led ground forces around al-Bab after Moscow and Turkey started cooperating late last year over a ceasefire and diplomatic solution to the civil war.

Turkey has accused the US-led coalition of not providing its ground offensive sufficient air support, even though the coalition has carried out 19 strikes and 36 engagements in or near al-Bab targeting IS since January 1, the coalition's spokesperson Col. John L. Dorrian said on Wednesday.

"We are carrying out our efforts with the coalition forces, and Russia provides support from time to time as well," Turkish President Tayyip Erdogan said last week.

The dizzying array of armed actors on the ground and in the air risks an escalation of hostilities, whether intentional or accidental, including among the Turkish military and the rebels it backs one side, and the Syrian army and allied militia on the other.

The Syrian government opposes Turkey's intervention and has vowed to retake all of the war-torn country's sovereign territory. But Turkey's intervention has been carried out with the tacit approval of Russia, the Assad regime's main backer. 

A potential flashpoint appears to be along the main Aleppo-Al-Bab Highway. As Syrian government-aligned forces advance along the highway, Turkish-backed forces on Wednesday pushed closer to the strategic road to the southwest of al-Bab, the Syrian Observatory for Human Rights, a UK-based monitor said.

It added the Turkish move was an attempt to block the gains of Syrian government forces.

The Turkish military launched "Euphrates Shield" in August to clear IS from a stretch of its border and block the gains of the Syrian Kurds. The intervention has succeeded in creating a de facto buffer zone controlled by rebels it backs along a stretch of its border, an area that may in the future be used as a safe zone for refugees and the internally displaced.

The buffer zone has achieved two main goals of the operation: clearing IS from the border and blocking the YPG from linking Kurdish-controlled areas in northeastern and northwestern Syria.

But the fight for al-Bab, located 30 kilometers deep into Syria territory, has exposed the limits of the Turkish military, the second largest in NATO. In November, Erdogan said al-Bab would fall quickly, but the operation has become bogged down. Erdogan has vowed to press on to take al-Bab and the issue has become an issue of national pride in Turkey.

At least 50 Turkish soldiers and dozens of rebels have died during the nearly two-month operation. Critics of the military operation say it now lacks an exit strategy or clear objectives, if or when al-Bab is captured.

The Turkish military has been weakened in the wake of wake of last July's failed coup attempt. Thousands of soldiers and officers have been dismissed or arrested in Turkish President Recep Tayyip Erdogan's post-coup purge, damaging the military's fighting ability and morale. In a sign of how far the purge has gone, several suspected coup plotters missed their hearing last month in Istanbul because they were fighting in al-Bab. On top of that, the military faces a bloody Kurdish insurgency at home. 

cw/sms (AFP, Reuters)