United Nations, Aug 1 (IANS): Calling the twin strikes by Israel killing senior leaders of Hamas and Hezbollah during a 24-hour period a "dangerous escalation", UN Secretary-General Antonio Guterres has called for an international diplomatic push to prevent a broader regional conflict.

"The international community must work together to urgently prevent any actions that could push the entire Middle East over the edge, with a devastating impact on civilians," the UN chief's Spokesperson Stephane Dujarric said on Wednesday.

Hamas leader Ismail Haniyeh was killed in an audacious strike inside Iran on Wednesday during his visit for the swearing-in of newly-elected Iranian President Masoud Pezeshkian, according to Hamas.

A short while earlier, Hezbollah commander Fuad Shukr was killed in an air strike in Beirut.

"The Secretary-General believes that the attacks we have seen in South Beirut and Tehran represent a dangerous escalation at a moment in which all efforts should instead be leading to a ceasefire in Gaza, the release of all Israeli hostages, a massive increase of humanitarian aid for Palestinians in Gaza and a return to calm in Lebanon and across the Blue Line that separates Lebanon from Israel," Dujarric said.

While Guterres has been calling for maximum restraint, it alone is not enough "at this extremely sensitive time" and he "urges all to vigorously work towards regional de-escalation", the spokesperson added.

Iran's UN Mission warned of an escalation, saying in an X post: "The response to an assassination will indeed be special operations -- harder and intended to instill deep regret in the perpetrator."

While Israel military confirmed it had taken out Shukr, Israel was silent on the killing of Haniyeh, a serious setback to ceasefire efforts in Gaza because the Qatar-based leader was a key negotiator with Israel for a ceasefire and the return of hostages taken by Hamas during the October 7 attack.