UN Secretary-General Antonio Guterres urged Sunday an immediate halt to the Israel-Hamas war in Gaza, the return of hostages and a "surge" in humanitarian aid to the besieged Palestinian territory.

"I repeat my call, the world's call for an immediate humanitarian ceasefire, the unconditional release of all hostages and an immediate surge in humanitarian aid. But a ceasefire will only be the start. It will be a long road back from the devastation and trauma of this war," Guterres said in a video address to an international donors' conference in Kuwait.