The German government has pledged to significantly increase its funding for the UN agency that supports Palestinian refugees after the United States cut its aid.

German Foreign Minister Heiko Maas said the funding crisis for the United Nations Relief and Works Agency (UNWRA) was fueling uncertainty.

“The loss of this organization could unleash an uncontrollable chain reaction,” he said.

Germany had already provided 81 million euros ($94 million) in aid for UNWRA this year, he said, and was preparing to increase its contribution. He gave no figure.

“We are currently preparing to provide an additional amount of significant funds,” Maas said in a letter to European Union foreign ministers that was seen by Reuters.

Maas said it was clear that the added German funds would not cover a $217 million deficit left by the US withdrawal, and urged the European Union and other states to work toward “a sustainable finance basis for the organization.”

It is part of a broader push by Maas to take a more assertive stance in disagreements with the United States on a range of issues including trade, military spending and climate change.