Israeli troops in the northern Gaza Strip opened fire on Palestinians scrambling for food aid on Thursday in a chaotic incident that the Hamas-run health ministry said killed 112 people, drawing sweeping condemnation worldwide.

Though there were conflicting reports on how the predawn incident unfolded, the Israeli military said a "stampede" occurred when thousands of Gazans surrounded a convoy of 38 aid trucks, leading to dozens of deaths and injuries.

It also spurred heated exchange at the Human Rights Council in Geneva, where Palestinian Ambassador Ibrahim Mohammad Khraishi confronted his Israeli counterpart about the reported casualties.

"Are these human shields? Are these Hamas combatants?" Khraishi asked.

At Kamal Adwan Hospital in Gaza, a Palestinian woman said: "We are under siege. Take pity on us. Ramadan is coming soon. People should look at us. Pity us."

The United Nations said 2.2 million people — the vast majority of Gaza's population — are threatened with famine, particularly in the north where destruction, fighting and looting make the delivery of food almost impossible.

"There were crowds of people, but the occupation (forces) kept firing toward us," one young man said while lying on the dirty, crowded floor at Kamal Adwan Hospital waiting for treatment. He was among those wounded in the chaos.

Ali Awad Ashqir, who had gone to get some flour for his starving family, had been waiting for two hours when violence erupted.

"At approximately 4 am, the trucks began to arrive. The moment they arrived, the occupation army fired artillery shells and guns," he said.

Hossam Abu Safiya, director of Kamal Adwan Hospital, said all casualties were hit by "bullets and shrapnel from occupation forces".

Ashraf al-Qudra, spokesman for Gaza's health ministry, denounced what he called a "massacre", saying 760 people were also wounded and blaming Israeli troops.