The Turkish army is suffering unexpectedly serious losses in men and equipment as it engages in its first real battle against Isis fighters holding al-Bab, a small but strategically placed city north east of Aleppo. Turkish military commanders had hoped to capture al-Bab quickly when their forces attacked it in December, but they are failing to break through Isis defences.

At least 47 Turkish soldiers have killed and eleven tanks disabled or destroyed according to the Turkish military expert Metin Gurcan writing in al-Monitor. Isis have posted a video showing a Turkish tank being destroyed, apparently by an anti-tank rocket and Isis fighters looking at the wreckage of other armoured vehicles.

The Turkish military intervention in northern Syria, known as Operation Euphrates Shield, which began on 24 August last year has also led to heavy civilian casualties. The Syrian Observatory for Human Rights, citing local witnesses, says that 352 civilians including 77 children and 48 women have been killed by Turkish artillery bombardments and air strikes over the last five months. Drone footage taken by Isis shows that the buildings in al-Bab, that once had a population of 100,000, have been devastated.

Turkey had intended to make a limited military foray into the territory between the Turkish frontier and Aleppo city 40 miles further south which would make it a serious player in the Syrian conflict. It would drive Isis from its last big stronghold in northern Syria at al-Bab and, above all, prevent the Syrian Kurdish People’s Protection Units (YPG) from linking up their enclaves at Kobani and Qamishli with one at Afrin, north west of Aleppo.

The strategy has proven far more costly and slower to implement in the face of determined and skilful Isis resistance than Ankara had foreseen. It wanted primarily to rely on Arab and Turkman militiamen under Turkish operational control, though these would be nominally part of the Free Syrian Army (FSA) umbrella group. These proxies would be backed up by Turkish artillery, air strikes and a limited number of Turkish ground troops.

The plan seemed to work in the beginning as the Turkish forces took over the Isis-held town of Jarablus, where the Euphrates River crosses the Turkish border. But swift success here came because Isis did not fight, its men retreating or shaving off their beards and melting into the local population. But when the Turkish-backed FSA advance failed to break through Isis lines in and around al-Bab, Turkey had to reinforce them with its own units which now do the bulk of the fighting.

In Pictures: The crisis unfolding in Syria Show all 30 1 /30 In Pictures: The crisis unfolding in Syria In Pictures: The crisis unfolding in Syria A Syrian family arrives at a checkpoint, manned by pro-government forces, at the al-Hawoz street roundabout, after leaving Aleppo's eastern neighbourhoods Getty In Pictures: The crisis unfolding in Syria A Syrian woman, fleeing violence in the restive Bustan al-Qasr neighbourhood, reacts as she stands with her children in Aleppo's Fardos neighbourhood, after regime troops retook the area from rebel fighters Getty In Pictures: The crisis unfolding in Syria Syrian pro-regime fighters, gesture as they drive past resident fleeing violence in the restive Bustan al-Qasr neighbourhood, in Aleppo's Fardos neighbourhood Getty In Pictures: The crisis unfolding in Syria Syrian rebels withdrew from six more neighbourhoods in their one-time bastion of east Aleppo in the face of advancing government troops, the Syrian Observatory for Human Rights said Getty In Pictures: The crisis unfolding in Syria Syrian rebels withdrew from six more neighbourhoods in their one-time bastion of east Aleppo in the face of advancing government troops, the Syrian Observatory for Human Rights said Getty In Pictures: The crisis unfolding in Syria Syrian residents, fleeing violence in the restive Bustan al-Qasr neighbourhood, arrive in Aleppo's Fardos neighbourhood , after regime troops retook the area from rebel fighters Getty In Pictures: The crisis unfolding in Syria Syrian pro-regime fighters, gesture as they drive past residents fleeing violence in the restive Bustan al-Qasr neighbourhood, in Aleppo's Fardos neighbourhood Getty In Pictures: The crisis unfolding in Syria Syrian residents, fleeing violence in the restive Bustan al-Qasr neighbourhood, arrive in Aleppo's Fardos neighbourhood, after regime troops retook the area from rebel fighters Getty In Pictures: The crisis unfolding in Syria Syrian residents, fleeing violence in the restive Bustan al-Qasr neighbourhood, arrive in Aleppo's Fardos neighbourhood Getty In Pictures: The crisis unfolding in Syria A Syrian pro-regime fighter speaks with a child, as residents flee violence in the restive Bustan al-Qasr neighbourhood. Syrian rebels withdrew from six more neighbourhoods in their one-time bastion of east Aleppo in the face of advancing government troops AFP/Getty Images In Pictures: The crisis unfolding in Syria Smoke rises as seen from a governement-held area of Aleppo, Syria Reuters In Pictures: The crisis unfolding in Syria Syrian soldiers targeting rebels-held areas in the eastern neighborhoods in Aleppo, Syria. According to media reports, the army is now holding on 99 percent of Aleppoís eastern neighborhoods EPA In Pictures: The crisis unfolding in Syria Syrian pro-government forces patrol Aleppo's eastern al-Salihin neighbourhood after troops retook the area from rebel fighters Getty In Pictures: The crisis unfolding in Syria Syrian soldiers rest following the battle at al-Sheik Saeed neighborhood in Aleppo, Syria EPA In Pictures: The crisis unfolding in Syria A Syrian pro-government fighter walking past closed shops in the Bab al-Nasr district of Aleppo's Old City. Once renowned for its bustling souks, grand citadel and historic gates, Aleppo's Old City has been rendered virtually unrecognisable by some of the worst violence of Syria's war Getty In Pictures: The crisis unfolding in Syria The crucial battle for Aleppo entered its 'final phase' after Syrian rebels retreated into a small pocket of their former bastion in the face of new army advances. The retreat leaves opposition fighters confined to just a handful of neighbourhoods in southeast Aleppo, the largest of them Sukkari and Mashhad Getty In Pictures: The crisis unfolding in Syria Syrian civilans arrive at a checkpoint, manned by pro-government forces, at the al-Hawoz street roundabout, after leaving Aleppo's eastern neighbourhoods. Syria's government has retaken at least 85 percent of east Aleppo, which fell to rebels in 2012, since beginning its operation Getty In Pictures: The crisis unfolding in Syria Syrian civilians flee the Sukkari neighbourhood towards safer rebel-held areas in southeastern Aleppo Getty In Pictures: The crisis unfolding in Syria Syrians celebrate in the government-held Mogambo neighbourhood of the northern Syrian city of Aleppo, after rebel fighters retreated into a small pocket of their former bastion in the face of new army advances Getty In Pictures: The crisis unfolding in Syria Syrians celebrate in the government-held Mogambo neighbourhood of the northern Syrian city of Aleppo, after rebel fighters retreated into a small pocket of their former bastion in the face of new army advances. The fall of Aleppo would be the worst rebel defeat since Syria's conflict began in 2011, and leave the government in control of the country's five major cities Getty In Pictures: The crisis unfolding in Syria A Syrian refugee camp in the Bekaa Valley, Lebanon, close to the Syrian border PA wire In Pictures: The crisis unfolding in Syria Syrian refugee Aliya inside the tent where she lives with her husband and ten children in a camp in the Bekaa Valley, Lebanon, close to the Syrian border PA wire In Pictures: The crisis unfolding in Syria Syrian refugee women and children outside the entrance to their tents in the refugee camp in the Bekaa Valley, Lebanon, close to the Syrian border PA Wire In Pictures: The crisis unfolding in Syria A Syrian refugee camp in the Bekaa Valley, Lebanon, close to the Syrian border PA wire In Pictures: The crisis unfolding in Syria A Syrian refugee camp in the Bekaa Valley, Lebanon, close to the Syrian border PA Wire In Pictures: The crisis unfolding in Syria A Syrian refugee woman outside the entrance to the tent where her family live, in the refugee camp in the Bekaa Valley, Lebanon, close to the Syrian border PA wire In Pictures: The crisis unfolding in Syria A vehicle drives past a mosque at night in Idlib, Syria. Picture taken with a long exposure Reuters In Pictures: The crisis unfolding in Syria Damaged buildings stand in the rebel-controlled town of Binnish in Idlib province, Syria Reuters In Pictures: The crisis unfolding in Syria The night sky is seen through damaged windows in the rebel-controlled town of Binnish in Idlib province, Syria Reuters In Pictures: The crisis unfolding in Syria Damaged buildings stand in the rebel-controlled area of Maaret al-Numan in Idlib province, Syria Reuters

Turkish leaders blamed their problems partly on the US which has failed to make more than a few air strikes in support of the al-Bab offensive. The US does not want to aid militarily a Turkish intervention aimed primarily at the YPG, who have proved the most effective US ally against Isis in Syria. The YPG has at least 25,000 battle-tested ground troops who are backed up by the massive firepower of the US-led air coalition. Ankara is hoping that the new Trump administration will be less cooperative with the Kurds and more so with Turkey.

Isis is using an effective cocktail of tactics similar to those which it employed to slow down the offensive of the Iraqi security forces in east Mosul which took them three months to capture. These tactics include frequent use of suicide bombers driving vehicles packed with explosives (VBIEDs),often especially armoured in Isis workshops so they are difficult to stop.

“Isis uses VBIEDs to disrupt its enemies’ field planning, organisation and morale,” says Mr Gurcan. “With tunnels, Isis maintains mobility, despite air attacks.” As in Mosul, Isis is able to move small mobile units containing snipers, specialists using ant-tank missiles and suicide bombers from house to house without exposing them to superior enemy fire power. The Turkish forces have been unable to encircle al-Bab and cut the main supply route to Raqqa, the de facto capital of Isis in Syria.

Turkey benefited at this week’s peace talks in Astana in Kazakhstan from being one of three foreign powers – the others being Russia and Iran – with ground troops in Syria. It had previously provided crucial aid, sanctuary and a near open border to the Syrian armed opposition. Reinforced by a diplomatic marriages of convenience with both Russia and Iran, Turkey has acquired significant influence over the outcome of the six-year long war in Syria. But the slow military progress at al-Bab shows Turkey’s growing military engagement in Syria is coming at a price – even in its initial phases.

The fighting in and around al-Bab underlines an important weakness of the plans announced at Astana to bolster the current shaky Syrian ceasefire announced on 30 December. The two most powerful rebel military movements, Isis and Jabhat Fateh al-Sham, formerly al-Nusra, al-Qaeda’s branch in Syria, are not included in the ceasefire and have no reason to abide by its terms. On the contrary, Nusra has launched an offensive in west Aleppo province to eliminate rebel groups sympathetic to peace talks and a ceasefire.