John Ging, the director of operations for the United Nations refugee agency in Gaza, said Thursday that Israel’s blockade was creating growing misery there by choking off basic humanitarian supplies like food, medicine, clothes and blankets as well as school supplies.

He also criticized the leadership of Hamas for letting its police force run wild, attacking a distribution center for the needy to cart off supplies.

“We are neither getting in the volume nor the range of supplies that we need here,” Mr. Ging told reporters at the United Nations, speaking via video link-up from Gaza. “This is creating a lot of misery among the people.”

In one example, Mr. Ging said that the teachers in the schools run by the United Nations Relief and Works Agency had worked throughout the three-week Israeli bombardment that ended Jan. 18 to create a new human rights curriculum. But because Israel was blocking paper supplies, the textbooks and workbooks could not be printed, so some 60 percent of the children in United Nations schools lack books.

The human rights curriculum was designed to combat extremism, he said, a growing problem in the wake of the Israeli bombardment. Ordinary Gazans are particularly frustrated, he said, because they have seen news reports about generous donations from around the world stuck just outside the enclave. It is premature to talk about Gaza’s reconstruction until the issue of access for basic humanitarian supplies is fixed, Mr. Ging said.

Israel has maintained a strict blockade of Gaza since Hamas took power there in a brief civil war with its secular rival, Fatah, in June 2007.

As to Hamas, Mr. Ging called on its leadership to rein in its rank and file after armed policemen looted blankets and food from a United Nations compound. While senior Hamas leaders remained in hiding, “those above the ground seem bent on acting in a reckless manner,” he said. It was the first such incident, he said, and the agency will halt all distributions if it continues.