(CNN) Two major offensives in northern Syria -- one by the Turkish army and the other by the Syrian regime -- are threatening to derail alliances and provide ISIS and other jihadist groups with fresh opportunities.

The Turkish army began Operation Olive Branch on January 20: its goal is to eradicate the Kurdish militia in the Afrin region and establish a buffer zone along the border. The operation has run into determined Kurdish resistance, with seven Turkish soldiers killed at the weekend.

In neighboring Idlib, the Syrian army -- backed by Russian airpower -- is making advances from the south. Much of Idlib is under the control of the jihadist Hayat Tahrir al Sham (HTS), a former affiliate of al Qaeda. But remnants of ISIS are have also converged on the area, according to multiple local accounts and the group's own propaganda.

This surge in conflict has jeopardized Russia's efforts to extend "deconfliction zones" in Syria as a stepping stone to a broader settlement. Idlib was declared as one of those zones. There's certainly no "deconfliction" there at the moment.

The United Nations Commission of Inquiry on Syria says "the scale and ferocity of attacks has increased dramatically, resulting in multiple reports of civilian casualties," and three hospitals being hit. It is investigating reports that weaponized chlorine was used in the town of Saraqib.

Turkey's 'Olive Branch'

Elizabeth Teoman at the Institute for the Study of War in Washington says Turkish forces and their allies among Syrian rebel groups "have made slow but steady progress on multiple fronts along the Syrian-Turkish border amid fierce Kurdish resistance and adverse weather," and now control a strip some 15 kilometers wide.

Turkey regards the Kurdish YPG, which controls a large chunk of northern Syria, as part of the Kurdish separatist group PKK that has waged an insurgency on Turkish soil for three decades, and sees both as part of the same terrorist organization. While many western governments agree the PKK is a terrorist group, they don't apply the label to the YPG, which has been an effective force in Syria against ISIS.

Turkish officials have been angered by criticism of the Afrin campaign, with Prime Minister Binali Yildirim speaking of "smear campaigns" by Turkey's allies. "If this [NATO] alliance is to persist, you will ignore words of looters, and accredit the words of Turkey, a trustworthy friend," he said at the weekend.

The US sees the Turkish campaign as distracting attention from the task of finishing off ISIS. Major General Felix Gedney, Deputy Commander of the joint task force fighting ISIS, tweeted at the weekend: "Military operations in #Afrin, #Syria are placing @Coalition's #DefeatDaesh mission at risk."

According to many observers, the YPG's attention has shifted from the ISIS mission towards the 400-kilometer stretch of the Turkish border it currently controls. YPG commanders warn that unless the US-led coalition somehow stops the Turkish offensive, they will be less enthusiastic about going after ISIS and may even abandon positions in Deir Ezzor, where the terror group is still active.

Metin Gurcan, a Turkish security analyst and columnist with al Monitor, says Turkey is unlikely to be moved. Its main objective in Afrin is less the elimination of YPG militants than to show it's a player in Syria -- and to "influence the strategic preferences of the US and Russia."

The question is whether Turkey expands its military operation to Kurdish-controlled areas where the US has a presence, like Manbij. US Homeland Security Advisor Tom Bossert warned at Davos about two weeks ago of the "grave consequences" should Turkish troops clash with US-backed forces fighting ISIS, Bloomberg reported

Gurcan says there is a real danger of Turkish-backed rebels and the YPG clashing in Manbij, with neither Turkey nor the US able to restrain their local allies.

Complicating the picture is the possibility that the regime of Syrian President Bashar al-Assad is helping the Kurds in an effort to combat Turkish influence in northern Syria.

Teoman says "Assad has allowed the YPG and allied groups to deploy reinforcements to Afrin through regime-held terrain." And she adds that "Assad and Iran may be providing advanced weapons systems to the YPG," whose use of anti-tank missiles has impeded the Turkish operation.

It's a typically Syrian scenario: 'the enemy of my enemy' is a temporary friend.

But the consequences of the Afrin offensive are broader than the age-old rivalry between Kurdish armed groups and the Turks. It could threaten to further destabilize Syria, taking the seven-year war to uncharted waters, and potentially reviving ISIS in the process.

Where ISIS went

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For much of 2017, the Syrian Democratic Forces (of which the YPG is the leading element) and the Syrian regime chipped away at ISIS' territorial holdings in northern Syria, culminating in the fall of Raqqa and Deir Ezzor. But several thousand ISIS fighters escaped alive.

Some continue to fight in remote areas along the Syria/Iraq border. US airstrikes last month killed some 150 militants at an ISIS headquarters near As-Shafah, close to the Iraqi border. Those strikes -- just as Turkey launched its Afrin operation -- were guided by SDF forces on the ground, the US-led coalition noted pointedly.

Other ISIS groups have gone deeper into the Iraqi desert. But many have moved to other parts of Syria, according to US officials and analysts.

For the Assad regime, those ISIS remnants are a mixed blessing. They are useful in that their targets include other rebel groups. (ISIS is very good at internecine warfare with rival jihadists.) But since arriving in the provinces of Hama and Idlib in recent months, ISIS fighters have also attacked regime forces, capturing and killing a number of Syrian soldiers last month.

On January 24, the ISIS-affiliated Amaq news agency posted a video purporting to show two Syrian soldiers who had been captured in southern Idlib.

Jennifer Cafarella, also at the Institute for the Study of War, told CNN that "ISIS is advancing into Idlib province on the heels of pro-regime forces, which are not attempting to block its advance."

Recently, a British jihadist, Lucas Kinney, appeared in a video calling on former fighters to resume their role in the Syrian jihad and urged Muslims in the region to come and fight. It was impossible to identify his location.

Another sign that ISIS has regained its footing is the uptick in its propaganda output. A study by the SITE Intelligence Group shows that in the first half of January there was a sharp increase in the number of ISIS communiqués and photo reports compared to previous months.

There may be more opportunities to come. The Idlib offensive being waged by the Syrian army threatens the synchronized strategy of Russia, Turkey and Iran for ending the conflict. They each have different priorities.

Russia wants "to minimize its costs and losses in Syria in order to avoid jeopardizing Putin's narrative of having ended the civil war, " according to Cafarella. But Turkey is supporting anti-Assad groups in north-west Syria (in part to block Syrian forces from interfering with Turkey's Afrin operation).

The movement of Turkish forces further south has infuriated the regime and its Iranian allies, which see the zone around the city of Aleppo as their power center, according to Gurcan, the Turkish security analyst.

Russian airpower undoubtedly turned the tide of the Syrian war, but Moscow is struggling to convert territorial advantage into meaningful peace. Its national dialogue conference in Sochi on January 30 was based on the assumption that Assad would remain in power. But the opposition was having none of it, and the conference went nowhere.

Now militant Islamists in northern Syria suddenly have dueling calls to jihad, says Gurcan -- against Assad's forces and Russia and against the "godless" YPG.

For the Russians, it's far from "mission accomplished."