The discovery has escalated tensions, with Israel accusing the agency of collaborating with Hamas and a dozen UNRWA staff members allegedly participating in an attack on Israel.

This has led to a freezing of the agency's funds, donor suspensions, and investigations, with Israel also halting its tax benefits and impeding aid.

Journalists were taken to see the tunnels, one of which runs beneath the UNRWA facility's courtyard. An underground room fitted with electrical equipment suggests it powered the tunnels, but Hamas's use of this infrastructure has not been conclusively proven.

UNRWA, led by Commissioner-General Philippe Lazzarini, stated they were unaware of the underground activities and an independent inquiry is needed, though it is currently not possible due to the conflict.

The facility in Gaza has been destroyed, and a tunnel entrance was exposed by digging. Reporters saw a half-kilometer stretch of tunnel with multiple doors under the UNRWA buildings. A room with computers connected to the tunnel via wires was also observed.

Hamas admits to creating extensive tunnel networks in Gaza for military purposes, which Israel aims to eliminate by their offensive, asserting that these tunnels endanger civilians by their proximity to public buildings and humanitarian facilities.

UNRWA maintains they lack military expertise for such inspections and were unaware of the tunnel activities. They last inspected the site in September.

During a recent operation, Israeli forces found weapons inside the tunnels, and the extent of the destruction wrought over four months includes thousands of Palestinian casualties, hostages, and severe infrastructural damage.

The scale of the humanitarian crisis is significant, and the remnants of the UNRWA headquarters show the intensity of the conflict, with relics of upheaval and occupation in the wake of the violence.