Syria's status quo has been "radically altered" in a matter of days, with a surge in fighting resulting in an "extremely fluid and dangerous" situation, the UN Special Envoy for the country warned on Tuesday.
Geir Pedersen told the Security Council the country faced grave risk of further division that was in no Syrian's interest.
"As I brief you today, a vast swathe of territory has come under the control of non-State actors, including the terrorist group Hay'at Tahrir al-Sham and armed opposition groups, including the Syrian National Army," he said .
"These groups now de facto control territory containing what we estimate to be some seven million people, including Aleppo - Syria's second biggest city and a vast and diverse metropolis of more than two million people."
He added that Syrian Government forces have regrouped in Hama, but their defences are under pressure as the opposition forces advance closer to the city. Both sides have escalated attacks, with pro-Government airstrikes targeting civilian infrastructure, including hospitals, and Hay'at Tahrir al-Sham firing barrages of drones and rockets.
Civilians have suffered casualties on both sides, he told ambassadors.
Tensions in the northeast
Mr. Pedersen also reported heightened tensions in northeast Syria, where United States-supported Syrian Democratic Forces (SDF) seized villages citing an imminent threat by the Islamic State in Iraq and the Levant (ISIL/Da'esh).
Israeli airstrikes were also reported on Damascus and the Syrian-Lebanese border this week, further destabilising the region.
The Special Envoy outlined two core messages, the first: an urgent need for de-escalation and calm.
"The last fourteen years of conflict have decisively shown that no Syrian party or existing grouping of actors can resolve the Syrian conflict via military means," he stressed, urging immediate de-escalation and adherence to international humanitarian law.
Credible political process vital
The second message was that the de-escalation must be accompanied by a credible political horizon for the Syrian people.
For almost five years, the "often elevated but somewhat contained" violence on the back of a "patchwork of ceasefire arrangements" was positive, he said. "But without being pegged to a political process to resolve the crisis, this amounted only to a conflict-management approach. And this is not enough."
He reiterated his warning that such an arrangement was unsustainable and has now unravelled entirely.
He stressed the need for a serious political process involving the Syrian parties and key international players.
"Syria will be in grave danger of further division, deterioration, and destruction…this should be in no-one's interest," he concluded.
