A senior UN official warned Wednesday that the lack of available funds for the reconstruction of Gaza and the fragile ceasefire between Israel and Hamas militants could lead to a renewal of hostilities in the coastal enclave.

During a Security Council briefing on the Middle East, Jeffery Feltman, the UN Under-Secretary-General for Political Affairs, also expressed “alarm” at reports of Hamas efforts to re-arm. He called the terror group’s test-firing of rockets, and its attempts to smuggle in materials for potential weapons use, “dangerous developments.”

Feltman said that the failure of world donors to deliver the billions of dollars in aid pledged to Gaza’s reconstruction, together with Israel’s withholding of PA tax revenues, was creating a dire humanitarian situation that threatened to reignite the conflict.

Get The Times of Israel's Daily Edition by email and never miss our top stories Free Sign Up

The under-secretary-general told the council that the countries who pledged some $5.4 billion to rebuild Gaza four months ago in Cairo had “yet to fulfill the vast majority of their pledges.”

“This is frankly unacceptable, and cannot continue if we hope to avoid another escalation in Gaza,” he told the 15-member council. Feltman warned that the fiscal challenge was putting “an almost unbearable strain on an already highly fractious environment.”

Feltman also condemned Israel’s withholding of $200 million of PA tax revenues in retaliation for the Palestinian Authority’s move to join the International Criminal Court. As a result, he said, the PA had been forced to borrow money to pay salaries, an approach he called “neither sufficient nor sustainable.” He called for Israel to reverse its decision immediately.

During the briefing, Feltman described the situation in Gaza as “increasingly worrisome,” and pointed to an International Monetary Fund study that found that, in 2014, the Palestinian economy contracted for the first time since 2006.

Almost six months after the war that devastated the Strip and left 100,000 Gazans homeless, Feltman said that only 75,000 residents had been cleared to receive construction materials, of whom 47,000 had been able to obtain the materials.

Israel and Egypt controls the border crossings into Gaza — including the delivery of construction materials — and seek to prevent the influx of materials that can be used to manufacture rockets or to build tunnels into Israel.

Gazan terrorists used the tunnels for several attacks during the summer war, sometimes penetrating deep into Israeli territory. Five soldiers were killed in one attack on an IDF post near Kibbutz Nahal Oz, and 11 soldiers died in all in the tunnel attacks.

Hamas, which seized control of Gaza in 2007 and is avowedly committed to destroying Israel, fired over 4,500 rockets at Israel during the 50-day conflict.

Unnamed security sources have said recently that Hamas is working to rebuild its tunnel infrastructure as well as rearm its depleted rocket arsenal.

In October, a Vanity Fair report confirmed rumors that before the summer’s war, Hamas was planning to insert hundreds of terrorists into Israel via underground tunnels, to kidnap and kill a large number of Israelis.

In a sign of growing impatience with the pace of reconstruction efforts, dozens of protesters forced their way into a UN office in Gaza on January 28, after the world body announced it was suspending an aid program to support home repairs and refugee shelter assistance.

Justin Jalil and AFP contributed to this report.