Antonio Guterres speaks to the media outside the Rafah border with the Gaza Strip on the Egyptian side on Saturday. AFP

UN chief Antonio Guterres, on a visit to the doorstep of Gaza on Saturday, appealed for a ceasefire to allow in more aid, saying the world has "seen enough" horrors in the Israel-Hamas war.

As Israeli forces pressed on with a multi-day raid on the territory's biggest hospital, Hamas officials reported 19 deaths at an aid distribution point on the outskirts of Gaza City.

Gaza's Hamas authorities said at least 19 people were killed and dozens wounded by Israeli "tank fire and shells" as they were waiting for desperately needed supplies.

The Israeli army denied it had fired on the crowd. "Preliminary findings have determined that there was no aerial strike against the convoy, nor were there incidents found of (Israeli) forces firing at the people at the aid convoy," it said.

In a similar scene earlier this month, the health ministry said Israeli fire had killed 20 people seeking aid in the same location, but the military accused "armed Palestinians" of opening fire on the crowd.

Antonio Guterres visits the Rafah border crossing between Egypt and the Gaza Strip, on Saturday. AP

Nearly six months of fighting, triggered by Hamas's October 7 attack on southern Israel, have led to dire humanitarian conditions in the besieged territory.

"Palestinians in Gaza -- children, women, men -- remain stuck in a non-stop nightmare," Guterres said at the Egyptian side of Rafah border crossing with Gaza, the main entry point for aid.

Most of the territory's 2.4 million people have sought refuge on the Gaza side of Rafah, where Israel has vowed to send in ground troops in its war against Hamas.

"I carry the voices of the vast majority of the world who have seen enough," Guterres said, deploring "communities obliterated, homes demolished, entire families and generations wiped out".

Agence France-Presse