Palestinian officials voiced outrage on Wednesday over President Donald Trump's threat to cut funding to the Palestinian Authority, calling his tweets "blackmail" in the aftermath of the U.S. administration's recognition of Jerusalem as Israel's capital. Palestinian President Mahmoud Abbas's office rebuffed the U.S. leader's remarks, saying that "Jerusalem is not for sale, neither for gold nor silver." Abbas' spokesman Nabil Abu Rdeneh said that "if the United States is keen on its interests in the Middle East, it must implement the international resolutions which call for a state on the 1967 borders with East Jerusalem as its capital." "Without this, the United States will push the region to the abyss," Abu Rdeneh added. Trump expressed frustration on Tuesday over the lack of progress in his attempts to broker peace between Israel and the Palestinians, and pointed his finger at the Palestinians. "We pay the Palestinians HUNDREDS OF MILLIONS OF DOLLARS a year and get no appreciation or respect," he tweeted. "But with the Palestinians no longer willing to talk peace, why should we make any of these massive future payments to them?" Trump upset the Palestinians last month by recognizing Jerusalem as Israel's capital and announcing plans to move the U.S. Embassy to the holy city. Israel seized control of the eastern part of Jerusalem in the 1967 Middle East war and annexed East Jerusalem in 1980, a move that has never been recognised by the international community. The Palestinians accused Trump of siding with Israel on the most sensitive issue in the conflict and subsequently said the U.S. could no longer serve as a mediator. Senior Palestinian official Hanan Ashrawi said the Palestinians "will not be blackmailed" by the president, adding that Trump "singlehandedly destroyed the very foundations of peace" by recognizing Jerusalem as Israel's capital last month. "Trump has sabotaged our search for peace, freedom and justice," she said Wednesday. American officials have been weighing possible retaliatory actions against the Palestinians for a U.N. resolution rejecting Trump's Jerusalem decision. The resolution passed last month by a 128-9 margin. U.S. Ambassador to the United Nations Nikki Haley presaged Trump's threat on Tuesday, saying the president doesn't want to give more funds "until the Palestinians are willing to come back to the negotiation table." "We still very much want to have a peace process. Nothing changes with that. The Palestinians now have to show they want to come to the table," Haley said. "As of now, they're not coming to the table, but they ask for aid. We're not giving the aid. We're going to make sure that they come to the table." In addition to its support for the Palestinian Authority, the U.S. is also the largest donor UNRWA, the U.N. agency that assists Palestinian refugees. The U.S. donated $355 million to UNRWA in 2016, nearly 30 percent of its total funding. A large portion of the organization's activity is focused on providing health care, education and food aid to Palestinians in the West Bank, Gaza Strip, Jordan, Syria and Lebanon. Ending this aid could precipitate a humanitarian crisis, particularly in impoverished Gaza, where a majority of residents are eligible for UNRWA support. UNRWA spokesman Chris Gunness said it had not been informed of any changes to U.S. funding at this time. Culture Minister Miri Regev, a senior member of Israeli Prime Minister Benjamin Netanyahu's Cabinet, said she was "very pleased" by Trump's call to cut funding to the Palestinians. She said the Trump administration's call to cut aid to UNRWA was "correct and important." *This story is edited by Ahram Online