UN Secretary-General Antonio Guterres (Photo:

He also said he hopes all parties in Gaza realize they will benefit from a permanent truce that could open the path to negotiating a two-state solution, and urged countries to ease sanctions on Syria.

"The most relevant question is Iran and relations between Iran, Israel, and the United States," Guterres said. "My hope is that the Iranians understand that it’s important to once and for all make it clear that they renounce nuclear weapons and, at the same time, engage constructively with the other countries of the region."

UN nuclear watchdog chief Rafael Grossi touched on the same theme in Davos, saying Iran is "pressing the gas pedal" on its enrichment of uranium to near weapons grade. Iran has always said its program is entirely peaceful and it has the right to enrich uranium to any level it wants.