Senior Chinese diplomat Wang Yi has warned the United States that political tensions between Beijing and Washington could undermine efforts by the world’s top two sources of greenhouse gas to cooperate in the fight against climate change

China’s State Councillor and Foreign Minister told US climate envoy John Kerry via video link on Wednesday that the two sides’ joint efforts to combat global warming were an “oasis”, according to a foreign ministry statement published late on Wednesday.

“But surrounding the oasis is a desert, and the oasis could be desertified very soon,” he said. “China-US climate cooperation cannot be separated from the wider environment of China-US relations.”

“We have shown our sincerity,” Wang was quoted by state broadcaster CCTV as saying. “Everyone who met with you will have to spend two weeks in quarantine, but we’re willing to pay that price, to discuss cooperation with the US on affairs of mutual concerns.”

Kerry told Wang that Washington remained committed to working with other nations to tackle the climate crisis, and encouraged China to do more to reduce emissions during the meeting, a State Department spokesperson said.