UNITED NATIONS - UN Special Envoy for Syria Geir Pedersen on Tuesday warned of a dangerous escalation in Syria.

"In repeated briefings, I have warned of the dangers of military escalation in Syria. I am here in person today to tell you that escalatory dynamics are indeed taking place, and this is worrying and dangerous," he told the Security Council in a briefing.

For many months there has been a slow increase in mutual strikes between the Syrian Democratic Forces (SDF) on one side, and Turkiye and armed opposition groups on the other, across northern Syria and with violence spilling over into Turkish territory, he said.

On Nov. 20, a week after the terrible bombing in Istanbul, which Turkiye attributed to the Kurdish People's Protection Units (YPG) in northern Syria and the Kurdistan Workers Party (PKK) -- a claim that the SDF denied -- Turkiye launched what it called the "Claw-Sword Air Operation." There were also reports of SDF strikes on Turkish forces and armed opposition-controlled areas and inside of Turkish territory, said Pedersen.

"The trend lines are deeply worrying, and carry real dangers of further escalation. Let me warn the Security Council of the scenario where large-scale military operations by one actor then have knock-on effects across all other theaters, unraveling the strategic stalemate that has brought a measure of relative calm for almost three years," he said.

Such an escalation would not only compound the devastating harm already meted out to Syrian civilians. It would also further endanger regional stability. Listed terrorist groups that are subdued but not defeated would immediately take advantage of any fresh instability, he warned.

UN Secretary-General Antonio Guterres has called for all parties to exercise maximum restraint and avoid escalation, whether in the air or on the ground, he said. "Let me stress that Turkiye, the armed opposition and the SDF should de-escalate now."

Pedersen called "loudly and clearly" on all actors to restrain themselves and engage in serious efforts to reinstate the calm, move toward a nationwide cease-fire and a cooperative approach to counter-terrorism in line with international humanitarian law.

He said the protection of civilians and civilian infrastructure is absolutely essential and that Syria needs less military activity and more focus on the political process and implementation of Security Council Resolution 2254.

"I feel we are at something of a fork in the road. I am troubled by the thought of a major military operation resuming after three years of relative calm. I fear what this would mean for Syrian civilians, and also for wider regional security. And I equally fear a scenario where the situation escalates in part because there is today no serious effort to resolve the conflict politically," said Pedersen.

There is a clear way forward: step back from escalation and restore relative calm on the ground; renew the framework in the Security Council on the humanitarian front; resume and make more substantive the Constitutional Committee meetings in Geneva; prioritize work on the detained, the disappeared, and the missing; deepen work toward identifying and implementing initial step-for-step confidence-building measures, he said.

Through this approach, incremental progress would be achievable. And this would help create a dynamic and pave the way for a more ambitious goal -- a comprehensive political solution that meets the legitimate aspirations of all Syrians and restores Syria's sovereignty, independence, unity and territorial integrity, he said, warning that the alternative is deeper suffering and more violence and instability.