The UN chief's remarks on Thursday took place at a brief meeting with journalists at UN headquarters in New York.
He urged the parties to the conflict to immediately come to their senses, and directly appealed to the United States and Israel to cease attacks on Iran.
Guterres then addressed the regime in Tehran, demanding that Iranian attacks on neighboring countries end immediately.
We are on the brink of a wider war that would encompass the Middle East - and which could lead to serious consequences across the world, Guterres said.
