"The Middle East is being pulled deeper into crisis, and the consequences reach far beyond the region," Guterres said at the Council's high-level open debate on advancing political solutions in the Middle East, Anadolu Agency reported.
"This week has brought wider attacks and further deterioration. I am profoundly concerned it could trigger a full resumption of conflict," he said.
"The Israeli-Palestinian conflict has gone unresolved for decades. It's time to get serious about the only credible way forward."
In the Gaza Strip, Guterres said the situation "is rapidly deteriorating," warning that Israel is declaring its intent to seize 70% of the territory.
Turning to the occupied West Bank, Guterres cited "alarming reports" of Israeli occupier violence averaging six attacks per day, warning that any attempted annexation "would, like the decades-long occupation, have no legal validity."
He said a ceasefire in the Persian Gulf is "more like a lesser fire," cautioning that restrictions on navigation near the Strait of Hormuz were generating global hardship.
Guterres also flagged risks to Syria's fragile peace, noting that consolidation "requires respect for its sovereignty and territorial integrity."