China will not invite international experts to investigate the source of Covid-19 until after securing the "final victory" against the virus, Beijing's UN ambassador in Geneva said Wednesday. China's priority is first beating the pandemic - and countering the "absurd and ridiculous" politicisation of the new coronavirus, Chen Xu told reporters in an online briefing. The World Health Organisation says it is waiting on an invitation from China to take part in its investigations into the animal origins of the virus, first reported in the city of Wuhan in December. Asked when the WHO could expect an invitation, Mr Chen replied: "The top priority, for the time being, is to focus on the fight against the pandemic until we win the final victory. "We need the right focus and allocation of our resources. "It's not that we are allergic to any kind of investigations, inquiries or evaluations," he said, as they could aid international efforts to prepare for future public health emergencies. "We need to race with time to save lives as much as we can," he added. "For whether or how the invitation will take place, we need to have the right priority setting at this moment, and on the other hand, we need the right atmosphere." Also on Wednesday, China hit back at US Secretary of State Mike Pompeo over his claims that the coronavirus originated in a lab in Wuhan, saying he "doesn't have any" evidence. Mr Pompeo said on Sunday that there was "enormous evidence" to show that the new coronavirus originated in a lab in China, further fuelling tensions with Beijing over its handling of the outbreak. "I think this matter should be handed to scientists and medical professionals, and not politicians, who lie for their own domestic political ends," said foreign ministry spokeswoman Hua Chunying at a regular press briefing. "Mr Pompeo repeatedly spoke up but he cannot present any evidence. How can he? Because he doesn't have any," she said. Mr Pompeo said Sunday in an interview that there was "enormous evidence" that the new coronavirus came out of a Wuhan lab. Most scientists believe the new virus, which emerged in China late last year, jumped from animals to humans - possibly from a market in Wuhan selling exotic animals for meat. The World Health Organisation said the US claims were "speculative".