The U.S. decision to end its decades of funding for the U.N. agency that aids Palestinian refugees and their descendants is "an attack on the rights of the Palestinian people," Palestinian President Mahmoud Abbas's spokesman said Saturday.

Nabil Abu Rudeneh said the move "does not serve peace but rather strengthens terrorism in the region." He said it was just the latest hostile act of the Trump Administration against the Palestinian people, after it recognized Jerusalem as Israel's capital and moved its embassy there. He said the Palestinian leadership was considering appealing to the U.N. Security Council to confront the American stance.

"This decision, which violates all resolutions of international legitimacy, requires the United Nations to take a firm stand against the U.S. decision and to take appropriate decisions," he said. "Whatever the size of the conspiracies aimed at liquidating the Palestinian cause, this will only increase the steadfastness of the Palestinian people and its leadership."

The U.S. supplies nearly 30 percent of the total budget of the U.N. Relief and Works Agency, or UNRWA, and had been demanding it carry out significant reforms to what it called an "irredeemably flawed operation." The decision cuts nearly $300 million of planned support.

UNRWA was established after Israel's 1948 War of Independence to singularly aid some 700,000 Palestinians who fled or were forced from their homes. Over time, the number bloomed to an estimated 5 million refugees and their descendants, mostly scattered across the region, who had an aid agency devoted solely to them while the rest of the world's refugees had to depend on the general UNHCR refugee agency.

Palestinian leaders assert the right of those refugees to return to land now under Israeli control. Israel has long argued the agency was politicized, ineffective and merely perpetuated the refugee crisis.

However, Palestinians have come to heavily rely on UNRWA's expansive health, education and social services, particularly in impoverished Gaza.

Adnan Abu Hasna, the UNRWA spokesman in Gaza, said they currently have 280,000 students in 274 schools and provide food aid to more than 1 million people.

"Stopping or cutting aid to UNRWA could really affect UNRWA's operations," he said. "We don't think cutting this aid will help stability or pushing the peace process, especially as UNRWA plays a big role in the stability of the region."

The move follows the American slashing of more than $200 million in bilateral aid to the Palestinians, and as Trump Mideast team plans its rollout of the much-anticipated yet unclear peace plan for Israel and the Palestinians. Trump has said that his recognition of Jerusalem had taken the prickly issue off the negotiating table and he may be trying to do the same with the refugees, another long-standing stumbling block.

The Palestinian leadership has been openly hostile to any proposal from the administration, citing what it says is a pro-Israel bias. The Palestinian Authority broke off contact with the U.S. after the Jerusalem announcement.

The Palestinians fear the U.S. is putting pressure on host countries like Lebanon, Jordan and Syria to absorb their refugee populations and eliminate the issue from future peace negotiations.

Seen by the Palestinians and most of the international community as providing a valuable safety net, UNRWA is viewed far differently by Israel.

Prime Minister Benjamin Netanyahu accuses the agency of perpetuating the conflict by helping promote an unrealistic Palestinian demand that refugees have the "right of return" to long-lost homes in what is now Israel. He has said UNRWA should be abolished and its responsibilities taken over by the main U.N. refugee agency.

Some in Israel have even tougher criticism, accusing UNRWA of teaching hatred of Israel in its classrooms and tolerating or assisting Hamas militants in Gaza.

Hamas spokesman Hazem Qassem accused the United States of going after UNRWA to eliminate the Palestinian right to return to their future homes.

"It's clear that Trump has shifted from taking sides with the Israeli enemy to being a partner in the assault on our Palestinian peoples' rights," he said. "All these decisions will not stop our people's struggle to gain freedom and return."