WASHINGTON -- The Trump administration has cut all funding to the United Nations Relief and Works Agency (UNRWA), questioning the organization's "fundamental business model" of servicing an "endlessly and exponentially expanding community" of declared Palestinian refugees.The move was previewed by US media outlets in recent weeks after e-mails from President Donald Trump's son-in-law, Jared Kushner, were leaked showing his interest in "disrupting" the UN body."The administration has carefully reviewed the issue and determined that the United States will not make additional contributions to UNRWA," the State Department said in a statement. "When we made a US contribution of $60 million in January, we made it clear that the United States was no longer willing to shoulder the very disproportionate share of the burden of UNRWA’s costs that we had assumed for many years.""Beyond the budget gap itself and failure to mobilize adequate and appropriate burden sharing, the fundamental business model and fiscal practices that have marked UNRWA for years– tied to UNRWA’s endlessly and exponentially expanding community of entitled beneficiaries– is simply unsustainable and has been in crisis mode for many years," it continued. "The United States will no longer commit further funding to this irredeemably flawed operation."The Palestinian Authority envoy to Washington, Husam Zomlot, said in a statement that the US was "reneging on its international commitments" by cutting its aid– the most generous of any country."It’s not up to the US administration to define the status of Palestinian refugees," Zomlot said. "The only status the US can define is, its own role in peacemaking in the region. By endorsing the most extreme Israeli narrative on all issues including the rights of more than 5 million Palestinian refugees, the US administration has lost its status as peacemaker and is damaging not only an already volatile situation but the prospects for future peace in the Middle East."A State Department official confirmed to The Jerusalem Post earlier this week that, while the administration would disapprove of UNRWA's definition for Palestinian refugees qualifying for aid, it would not redefine nor enumerate the category.UNRWA claims that the descendants of refugees from 1940s Mandate Palestine qualify as refugees themselves– a definition that has allowed the number of beneficiaries to balloon in recent years."We are very mindful of and deeply concerned regarding the impact upon innocent Palestinians, especially school children, of the failure of UNRWA and key members of the regional and international donor community to reform and reset the UNRWA way of doing business," the State Department said. "These children are part of the future of the Middle East. Palestinians, wherever they live, deserve better than an endlessly crisis-driven service provision model. They deserve to be able to plan for the future."US ambassador to the UN Nikki Haley and Secretary of State Mike Pompeo joined Kushner in support of the decision. The administration had already cut much of its aid to UNRWA earlier in the year."UNRWA can stay there, and we will be a donor if it reforms what it does," Haley told the Foundation for Defense of Democracies earlier this week. "If it goes and makes sure that they're not doing those teachings in textbooks, if they actually change the number of refugees to an accurate account. We will look back at partnering them."A spokesman for Palestinian Authority President Mahmoud Abbas called the US decision a "flagrant assault" against the Palestinian people, and a "defiance of UN resolutions.""Such a punishment will not succeed to change the fact that the United States no longer has a role in the region and that it is not a part of the solution."In Gaza, the Islamist group Hamas also condemned the US move as a "grave escalation against the Palestinian people.""The American decision aims to wipe out the right of return and is a grave US escalation against the Palestinian people," said Hamas spokesman Sami Abu Zuhri.Abu Zuhri told Reuters the "US leadership has become an enemy of our people and of our nation and we will not surrender before such unjust decisions."Reuters contributed to this report.