U.N. Secretary-General Antonio Guterres said on Tuesday he was "deeply alarmed" by a renewed escalation of violence in the Middle East and called on Israel to reopen crossings into Gaza.
"All attacks must stop immediately. The ceasefires in Lebanon, Iran & Gaza must be fully respected," he said in a post on X.
Israel struck targets in Iran on Monday for the first time since a ceasefire in April, after Iran fired missiles at Israel in what Tehran said was retaliation for Israeli strikes on Lebanon's capital.
Israel and Iran both called a halt to the exchange on Monday shortly after Trump told them to stop shooting, although they each left the door open to a possible resumption.
The most direct confrontation between the two countries since April threatened to wreck Washington's efforts to reach an agreement with Tehran to end their more than 3-month-old war.
Guterres also said Israel should open crossings it has closed into Gaza to allow for the flow of humanitarian aid.
"I'm also deeply concerned by Israel's decision to close crossings into Gaza & reiterate my call for the immediate reopening of all crossings to ensure the rapid, safe & unhindered passage of humanitarian assistance at scale throughout Gaza," he said.
A U.S.-brokered ceasefire between Israel and Hamas in place since October 2025 that includes guarantees of increased aid.
Israel and Hamas have repeatedly accused each other of violating the truce. Israeli strikes have killed more than 950 people since the truce, health officials say, while Israel says four soldiers were killed by resistance groups during the same period.
