Germany’s health minister on Wednesday lamented the formal U.S. notification of its withdrawal from the World Health Organization as a “setback for international cooperation” and said Europe would work to reform the U.N. health agency.

The comments from German Health Minister Jens Spahn epitomized concerns in Europe over the WHO’s largest contributor preparing to pull out following the Trump administration's complaints that the agency too readily accepted China’s explanations of its early handling of the coronavirus.

Spahn said on Twitter that more global cooperation, not less, is needed to fight pandemics, adding: “European states will initiate #WHO reforms.”

The United Nations and the U.S. State Department said Tuesday that the Trump administration had formally notified the U.N. that the United States would leave the WHO next year.

The notification, which could be rescinded by a new administration or if circumstances change, makes good on President Donald Trump’s vow in late May to terminate U.S. participation in the WHO. Trump has criticized the U.N. health agency for its response to COVID-19 outbreak and accused its officials of bowing to China.

The U.S. provides the WHO with more than $450 million per year and currently owes some $200 million in current and past dues.

Juergen Hardt, a foreign policy spokesman for German Chancellor Angela Merkel’s center-right coalition, said that the U.S. withdrawal damages American and Western strategic interests just as China, a key WHO member state, has been taking a greater role in international institutions.

“As the biggest contributor so far, the U.S. leaves a big vacuum,” Hardt said. “It is foreseeable that China above all will try to fill this vacuum itself. That will further complicate necessary reforms in the organization.”

“It is all the more important that the EU uses its political weight and strengthens its involvement in the WHO as in other international organizations,” he added.

Earlier Wednesday, Chinese Foreign Ministry spokesperson Zhao Lijian defended the WHO and said the U.S. move was “another demonstration of the U.S. pursuing unilateralism, withdrawing from groups and breaking contracts.”

Spanish Foreign Minister Arancha González Laya said the WHO needs “more autonomy” and that more preparation was needed for future pandemics.

“What we need today is more multilateralism and less national sovereignty as a guarantee for protecting our citizens, even if that means that we go against what others have said in other parts of the world,” González Laya told reporters. “Let’s not get carried away by siren songs.”

David Heymann, an American who is a former senior director at the WHO, said he was “very disappointed” at the U.S. decision to exit the agency. He said he expects Germany and other countries to step forward if the U.S. funding and expertise that has benefited WHO ends.

“As much as it would be terrible if the U.S. leaves WHO and leaves (with) that expertise it has provided throughout the years, the WHO would continue to function,” Heymann said.

Geir Moulson in Berlin, Aritz Parra in Madrid and Maria Cheng in London contributed to this report.