"The Gaza model must not be replicated in Lebanon," Guterres told reporters, also saying the wider war in the Middle East is "out of control," as the United States, Israel and Iran have carried out strikes for more than three weeks.

"Across the region, and far beyond, civilians are enduring serious harm and living under profound insecurity. I witnessed some of these consequences firsthand during my recent visit to Lebanon," he said.

"There, too, the war must stop. Hezbollah must stop launching attacks into Israel. And Israel must stop its military operations and strikes in Lebanon, which are hitting civilians the hardest."

In early March, Israeli Finance Minister Bezalel Smotrich threatened Beirut's southern suburbs -- a stronghold of Iran-backed Hezbollah -- with the same devastation that Israel has inflicted on Gaza in its war against militant group Hamas.

Beyond Lebanon, Guterres voiced alarm at the wider regional war triggered by US-Israeli strikes on Iran in late February that killed the country's supreme leader Ali Khamenei.

"The conflict has broken past the limits even leaders thought imaginable," he said.

"The world is staring down the barrel of a wider war, a rising tide of human suffering, and a deeper global economic shock. This has gone too far."

The UN chief also announced the appointment of French diplomat Jean Arnault as his special envoy to lead UN efforts regarding the conflict and its consequences.