United Nations Secretary-General Antonio Guterres said on Friday he is profoundly concerned by escalating tensions between Israel and Lebanon's Hezbollah and that UN peacekeepers are working to calm the situation and prevent miscalculation.

"One rash move - one miscalculation - could trigger a catastrophe that goes far beyond the border, and frankly, beyond imagination," he told reporters. "Let's be clear: The people of the region and the people of the world cannot afford Lebanon to become another Gaza."

Iran-backed Hezbollah has been firing rockets at Israel in solidarity with its Palestinian ally Hamas since the Gaza war erupted in October, forcing tens of thousands to flee homes in Israel, where political pressure is building for tougher action.

Tens of thousands of Lebanese have also fled their homes following Israeli strikes in south Lebanon.

Iran's mission to the United Nations said on Friday that Hezbollah has the capability to defend itself and Lebanon against Israel, warning that "perhaps the time for the self-annihilation of this illegitimate regime has come."

"Any imprudent decision by the occupying Israeli regime to save itself could plunge the region into a new war," Iran's UN mission posted on X.

A UN peacekeeping force UNIFIL, as well as unarmed technical observers known as UNTSO, have long been stationed in southern Lebanon to monitor hostilities along the demarcation line between Lebanon and Israel, known as the Blue Line.

"UN peacekeepers are on the ground working to de-escalate tensions and help prevent miscalculation," Guterres said.

"The world must say loudly and clearly: immediate de-escalation is not only possible – it is essential," he said. "There is no military solution."