China has rejected a plan by the World Health Organization (WHO) to continue investigating the origins of the new coronavirus. China’s vice minister of health, Zeng Yixin, dismissed on Thursday a WHO proposal made this month for further study. The official objected because the WHO plans to investigate the theory that the coronavirus may have escaped from a Chinese laboratory. “It is impossible for us to accept such an origin-tracing plan,” Zeng told reporters. He described the lab origin idea as a rumor that goes against common sense and science. The earliest known cases of the new coronavirus, which causes the disease COVID-19, were identified in the Chinese city of Wuhan in December 2019. The head of the WHO said earlier this month that the organization was seeking more information from China on the first days of the virus spread. “We are asking China to be transparent, open and cooperate,” WHO Director-General Tedros Adhanom Ghebreyesus said. “Especially on the information, raw data that we asked for in the early days of the pandemic,” he added. The investigation into the origins of the virus has become a diplomatic issue that has fueled China's worsening relations with the U.S. and other countries. The U.S. and others say China has not been completely open about what happened in the early days of the pandemic. China accuses critics of seeking to blame it for the health crisis and for politicizing the issue. Zeng repeated China's position that some data cannot not be completely shared because of privacy concerns. He urged the WHO to seriously review the considerations and suggestions made by Chinese experts.” He added that the issue should be treated “as a scientific matter” with no “political interference. Most scientists do not believe a lab escape was responsible for releasing the coronavirus. In a report released in March, the WHO said the new coronavirus likely started in bats before being passed on to humans through another animal. That report was carried out jointly between the WHO and China.