A Chinese official refuted U.S. President-elect Donald Trump’s claim that climate change is a “hoax” perpetrated by China at an international conference to address the issue in Marrakesh.

Liu Zhenmin, China’s vice foreign minister, joined a growing chorus of international leaders to condemn Trump’s denial of climate change science. Liu noted in his comments Wednesday that George H.W. Bush played an influential role in establishing a United Nations body to oversee climate change negotiations during his presidency, known as the U.N. Framework Convention on Climate Change, according to a Bloomberg report.

“If you look at the history of climate change negotiations, actually it was initiated by the IPCC with the support of the Republicans during the Reagan and senior Bush administration during the late 1980s,” Liu said, using an acronym for the U.N. body charged with researching the topic.

Diplomats from more than 190 countries are gathered in Marrakesh to discuss implementation of the Paris Agreement on climate change. The international deal, which took effect earlier this month, sets a path for the world to address climate change but now faces an uncertain future after Trump’s election. The President-elect has promised to cancel the deal and, while formal withdraw is complicated, he could easily ignore its provisions during his presidency.

Climate change emerged as a key area of cooperation for the U.S. and China in the last four years and many international climate experts say the partnership was crucial to securing the Paris Agreement. Without U.S. cooperation, many other signatories may feel little incentive to comply.

The comment is not the first from a Chinese official to condemn Trump’s stance on climate change. French President Francois Hollande, U.N. Secretary-General Ban Ki-moon, Brazilian Environment Minister Sarney Filho and others have also expressed concern over Trump’s climate change policy.

“The United States, the most powerful economy in the world, the second-largest emitter of greenhouse gases, must respect the commitments that were made,” said Hollande, according to an Associated Press report. “It’s not simply their duty, it’s in their interest.”

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Write to Justin Worland at justin.worland@time.com.