Jeremy Corbyn, leader of the U.K. Labour Party, speaks at a launch event for the party's local election campaign in London, U.K., April 9, 2018.

British Labour Party leader Jeremy Corbyn joined an international chorus of criticism against the U.S. decision to cut the entire aid budget to UNRWA, the UN agency in charge of assisting Palestinian refugees and their descendants.

"Shameful for the US to end its funding for UNRWA, a vital UN refugee agency," Corbyn wrote on his official Twitter account.

"The UK must help to fill the gap by boosting its contributions," he added, backing other international calls to make up for the retrieved U.S. contributions with additional funding from other donors.

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The UN Works and Relief Agency began operating in 1950. It helps around 5 million people, providing food aid, operating schools and running health centers. The U.S. is the largest donor to UNRWA: the announcement that it will cut funds deals a major blow to the organization.

"Support for Palestinian refugees is a vital commitment until there is a just and viable settlement of the Israel-Palestine conflict," Corbyn concluded in his tweet.

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But U.S. officials argue that UNRWA has perpetuated the Palestinian refugee crisis: By treating and supporting Palestinians displaced in the West Bank and Gaza, Jordan, Lebanon or Syria and their descendants as refugees, they accuse the organization of preventing integration and boosting the ambition to return to lands that are now part of the state of Israel.

Prime Minister Benjamin Netanyahu on Sunday lauded the U.S. for the decision, calling it a "blessed and important change."

Following the U.S. announcement on the end of UNRWA funding, The European Union issued a statement Saturday pledging to continue supporting UNRWA and potentially increase funding to the agency if deemed necessary. Germany said it is preparing a "substantial" increase in its contributions to the cash-strapped agency.