IS scored 'opportunistic' wins in Syria as Aleppo fell

The Syrian regime's all-out offensive to recapture Aleppo enabled the Islamic State group to regain territory elsewhere, including the historic city of Palmyra, and has dimmed prospects of defeating the jihadists, experts say.

"The resources deployed (by Damascus and its allies) to retake Aleppo have allowed IS to claim a series of opportunistic victories" in Syria, said Charles Lister of the US think-tank Middle East Institute.

During the assault by Syrian, Russian and Iranian forces on rebels in eastern Aleppo, IS jihadists recaptured the historic city of Palmyra on December 11 after losing it in March.

"Russia and Syria prioritised the defeat of the opposition in Aleppo city over the defence of Palmyra from IS, ultimately enhancing the threat posed by Salafi-jihadist groups in both northern and eastern Syria," Jonathan Mautner of the Institute for the Study of War (ISW) wrote on the Washington-based think-tank's blog.

He said the recapture of Palmyra highlighted "the inability of pro-regime forces to establish security across the entire country without sustained support from Russia and Iran, notwithstanding their recent success in Aleppo city".

- IS 'the big winner' -

IS "appears the big winner from the fall of Aleppo," said Jean-Pierre Filiu, a professor at the Paris School of International Affairs.

Not only did the group recapture Palmyra, its propaganda benefitted from "international passivity in the face of Aleppo's suffering", which encouraged the group's followers to launch attacks one after the other in Jordan and Germany, he said.

A shooting rampage in the Jordanian city of Karak left 10 dead on Sunday, the day before 12 people were killed in the truck attack on a Christmas market in Berlin. The main suspect, Anis Amri, was shot dead in Italy on Friday.

Still, IS controls only half the territory it seized in 2014 in Iraq and Syria, with its heaviest defeats coming this year at the hands of coalition forces.

In northern Syria, IS lost Kobane and Minbej, as well as Dabiq, a town of major symbolic importance to the jihadists because according to a Sunni prophecy, it will be the site of an apocalyptic battle between Muslim and Christian armies.

Al-Bab, its stronghold north of Aleppo, is under attack by Turkey, which launched an offensive four months ago to chase IS from its southern border.

But the jihadists still control Raqa, the Syrian capital of their self-proclaimed "caliphate".

They also control the banks of the Euphrates river all the way to the border with Iraq.

After the battle of Aleppo, "there is a de-facto division of Syria in two, with the Russians in the west and the Americans in the east," a European diplomat said.

Moscow is expected to continue supporting the regime of President Bashar al-Assad to recapture territory from the Syrian rebels, while Washington continues its fight against IS.

"The Russians want to recapture 'useful' Syria and leave the 'IS-land' quagmire to the West," the diplomat said.

On December 14, US Lieutenant General Stephen Townsend, who commands the air campaign of the anti-IS coalition, said that if the Russians do not try to retake Palmyra, the US-led coalition would "do what we need to do".

- Raqa remains a challenge -

But the main challenge remains the recapture of Raqa, the base from which IS has planned attacks in Europe and Arab countries.

The Syrian Democratic Forces (SDF), an Arab-Kurdish alliance backed by US ground and air forces, launched an offensive to retake Raqa in early November.

The Kurds' leading role has set alarm bells ringing in Ankara, which considers the main Syrian Kurdish YPG militia a "terrorist" group. Turkey is currently waging its own offensive inside Syria, targeting both IS and the Kurds.

Turkey worries that the SDF offensive against Raqa could allow it to put down roots in the city.

Meanwhile, with Moscow "indifferent to the fate of Raqa and the United States bogged down in the battle of Mosul" -- the main IS stronghold in Iraq -- Turkey could be emboldened to step up its intervention in Syria, Filiu said.