HAMILTON, Canada 

UN Secretary-General Antonio Guterres on Sunday warned that the US bombing of Iranian nuclear sites represents a "perilous turn" in a region already "reeling" from conflict, calling on all parties to prioritize diplomacy and restraint.

"Two days ago, in this very chamber, I made a direct appeal: Give peace a chance. That call was not heeded," Guterres said during an emergency UN Security Council session on Iran, which was requested by Tehran and backed by Russia.

Guterres said that "instead, the bombing of Iranian nuclear facilities by the US marks a perilous turn in a region that is already reeling."

Stressing that the Middle East "cannot endure another cycle of destruction," he warned: "We now risk descending into a rathole of retaliation after retaliation."

"To avoid it, diplomacy must prevail. Civilians must be protected. Safe maritime navigation must be guaranteed," Guterres stressed.

Emphasizing the importance of international law, he said: "We need a credible, comprehensive, and verifiable solution—one that restores trust—including full access to inspectors of the IAEA, as the UN technical authority in this field."

Calling the Nuclear Non-Proliferation Treaty (NPT) "a cornerstone of international peace and security," Guterres urged Iran to fully respect it and said all member states must adhere to the UN Charter and international humanitarian law.

"Peace cannot be imposed; it must be chosen," the UN chief stressed, urging the Security Council and "all member states to act with reason, restraint, and urgency. We cannot—and must not—give up on peace."

The emergency session comes following US President Donald Trump's announcement early Sunday that his forces bombed three Iranian nuclear sites in Fordo, Natanz, and Isfahan.

The US targeted Iran's nuclear sites with six bunker-buster bombs dropped on the Fordo facility with B-2 stealth bombers, along with dozens of submarine-launched cruise missile strikes on the Natanz and Isfahan facilities.

The attacks came as the latest escalation in a US-backed Israeli military assault on Iran since June 13, prompting Tehran to launch retaliatory attacks on Israel.

Israeli authorities said at least 25 people have been killed and hundreds injured since then in Iranian missile attacks.