The Syrian government has formally appealed to the United Nations over incursions into its territory by Turkish troops. The protest at the UN came amid reports that Turkish soldiers have crossed the border and entered the Syrian town of Jarablus on the western bank of the Euphrates River.

Turkish military action inside Syria threatens to escalate the internal conflict in that country and increase the threat of a confrontation between Turkey and Russia. Relations between Ankara and Moscow have remained tense since the November 24 Turkish shoot-down of a Russian warplane over Syrian territory.

Jarablus is under the control of the Islamic State of Iraq and Syria (ISIS), but has come under increasing pressure from forces of the Syrian Kurdish People’s Protection Units (YPG), which have received backing from Washington in its so-called war on ISIS.

Turkey, a NATO ally of the US, is supposedly part of the anti-ISIS coalition. But there is extensive evidence that the government of President Recep Tayyip Erdoğan has facilitated the flow of fighters, arms and money to the Islamist militia and tacitly sanctioned the smuggling into Turkey of oil produced by ISIS-controlled installations in Syria.

The primary Turkish interest in Syria has been to block the consolidation of an autonomous Kurdish region on Turkey’s southern border. The government in Ankara has declared that any attempt by the YPG to cross to the western bank of the Euphrates and link up the two Kurdish cantons of Kobane and Afrin would be a “red line” that would trigger Turkish military intervention.

ISIS fighters have reportedly offered no resistance to the Turkish incursion, underscoring the barely concealed collaboration between the Islamists and the Turkish state.

The Syrian Kurdish ARA News service reported that the Turkish army carried out an artillery attack on Tuesday against the YPG headquarters in the Syrian border town of Tel Abyad, wounding at least two Kurdish fighters and destroying three armored vehicles.

The city, which is north of the de facto ISIS capital of Raqqa, was retaken by YPG units in fighting with the Salafist jihadi militia last June.

Turkey’s warmongering in Syria is bound up with its bloody campaign of repression against the Kurdish population within Turkey itself. Amnesty International on Wednesday condemned the Turkish government for carrying out “collective punishment” against its Kurdish population through “round-the-clock curfews and other arbitrary measures which have left residents without access to emergency health care, food, water and electricity for extended periods.”

The repression has escalated steadily since the collapse last July of a two-year “peace process” between the government and the Kurdistan Workers’ Party (PKK). More than 300 civilians have been killed in the Turkish campaign, including at least 61 children. Just in the period of December 11, 2015 to January 8, 2016, 162 civilians lost their lives.

US Vice President Joe Biden arrived in Istanbul Thursday night for talks with Erdoğan and Prime Minister Ahmet Davutoğlu that will likely center on the twisted and multisided relationship between the Kurdish question, the campaign against ISIS and the Western-orchestrated war for regime-change in Syria.

Washington and Ankara both seek the toppling of the government of Syrian President Bashar al-Assad and both are hostile to Russian interests in the region. There are, however, major tactical differences between them.

While the US has voiced support for Erdoğan’s crackdown against the PKK and the Kurdish population inside Turkey, the Pentagon has dispatched “advisors” to aid the Kurdish fighters of the YPG on the Syrian side of the border, using them as ground troops to seize territory in the US-led bombing campaign against ISIS.

Erdoğan has allowed the US to use the Incirlik air base in Turkey to carry out airstrikes against ISIS positions in Syria, but his military has centered its own strikes on Kurdish forces there as well as in Iraq, where the government in Baghdad has denounced Turkish intervention as a violation of the country’s sovereignty.

Biden is expected to press for Turkey to seal off a 60-mile unsecured stretch of its border with Syria that serves as the principal supply line for ISIS. The Turkish government, however, far prefers ISIS control of the border zone over control by the Kurdish YPG.

Any move to secure the border will inevitably be accompanied by a Turkish intervention to halt a Kurdish advance, either through direct Turkish military occupation or through control over the area by other Al Qaeda-linked militias such as the al-Nusra Front, Ahrar al-Sham or Jaish al-Islam, all of which have enjoyed Turkish support.

The mounting conflicts threaten to upend talks scheduled in Geneva next Monday for the ostensible purpose of achieving a negotiated end to the nearly five-year-old civil war that has claimed the lives of roughly a quarter of a million Syrians and turned millions more into refugees.

US Secretary of State John Kerry allowed on Thursday that the talks could be put off for “a day or two.” Asked by reporters at the World Economic Forum in Davos whether there would be a delay, Kerry responded, “When you say a delay, it may be a day or two for invitations, but there is not going to be a fundamental delay.”

The “delay,” however, concerns precisely the issue of which parties are to receive invitations to attend. Washington and Moscow have agreed that both ISIS and the al-Nusra Front will not be included in any peace talks. However, the Obama administration is insisting that Salafist jihadi outfits such as Ahrar al-Sham and Jaish al-Islam, which share Al Qaeda’s essential outlook and methods, should be included as “moderate rebels.” The Russian government has insisted that they be excluded as “terrorists.”

Moscow, in turn, has called for the Syrian Kurdish YPG to be included in the talks, while Turkey has declared that it sees both it and ISIS as equally “terrorist.”

According to a report on the Foreign Policy web site, the United Nation’s special envoy for Syria, Staffan de Mistura, reported to the UN Security Council that Saudi Arabia was sabotaging his attempt to bring a broad range of Syrian opposition groups to the Geneva talks.

He said that the so-called High Negotiations Committee (HNC), cobbled together in Riyadh by the Saudi monarchy and dominated by Islamist militias, had rejected the participation of any other groups in the talks. He told the Security Council that the HNC and its “sponsors” insist on “the primacy and exclusivity of their role as ‘THE’ opposition delegation.”

These “sponsors” include not only the Saudi regime, but also Qatar, Turkey and the US itself. In a briefing Tuesday, State Department spokesman John Kirby said, “As we said after Riyadh, the opposition will be represented at that meeting by delegates chosen from the High Negotiating Committee and only from the High Negotiating Committee.”

Washington’s aim remains to secure through a combination of negotiations and continuing support for Islamist sectarian militias in Syria what it has so far been unable to achieve: the toppling of Assad and the imposition of a more pliant puppet regime. In continuing to press for this end, it has unleashed a series of bitter regional and international conflicts that threaten to escalate into a far wider war with devastating consequences for the region and the entire world.