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The US on Tuesday blamed Hamas for the destruction of UN centres in Gaza.
The UNRWA, the UN agency for Palestinians, said on Tuesday that its headquarters is now “destroyed beyond recognition” after one of the Gaza Strip's deadliest weeks.
Israeli strikes also destroyed four UNRWA schools.
But Washington pointed the finger at Hamas for the scale of the destruction.
A US State Department official told The National that President Joe Biden's administration is “outraged at reports that Hamas has operated near, within and under UNRWA facilities, putting civilians and humanitarian workers at risk”.
Gaza's government media office said an Israeli attack on the UNRWA-run Al Razi school killed at least 23 people and injured 73 others on Tuesday.
And Israeli strikes on Gaza at the weekend killed more than 90 Palestinians in Al Mawasi, a designated “safe zone” for civilians.
“Any number of casualties above zero is tragic, heartbreaking and indicative that more needs to be done to protect civilians in Gaza,” the official said.
The official said Washington “is co-ordinating with partners to get aid into Gaza through operational routes and safely onwards to those in need”.
The Department of Defence last week said that “more than 8,100 tonnes of humanitarian aid have been delivered” through the US-made humanitarian pier on Gaza's coast.
But this year, the Biden administration stropped funding for the UNRWA after Israel claimed that some of its staff members had been involved in the October 7 Hamas-led attack.
The UNRWA has warned that the halt on US funding would create a “huge gap” in the agency's support system amid an Israeli siege that has killed more than 38,700 Palestinians.
Since that pause, Mr Biden has signed into law legislation that blocked Washington from contributing financially to the UNRWA until 2025.
A growing movement in Congress has vowed to shut down the agency completely.
Republicans in the House of Representatives introduced the “Stop Support for UNRWA Act” this year.
If passed, it would ban any “voluntary or involuntary” US contributions to the Palestinian relief organisation and “to any successor or related entity, or to the regular budget of the United Nations for the support of UNRWA or a successor entity”.
