BEIJING — Chinese officials on Saturday offered a lengthy rebuttal to accusations by the World Health Organization that they had been slow to share data about the possible origins of the coronavirus, blasting some in the organization as political “tools” whose remarks were “intolerable.” Scientists from the Chinese Center for Disease Control and Prevention made the remarks at a news conference after weeks of mounting criticism from the WHO The WHO’s accusations referred specifically to the recent revelation that Chinese scientists had data on environmental and animal samples collected in Wuhan, the city central China where the virus first emerged, that they had not shared earlier. On Thursday, a top WHO official said that China’s “lack of data disclosure is simply inexcusable.” Shen Hongbing, the chief of China’s CDC, forcibly denied those charges.” We did not hide any cases, samples or testing and analysis results,” he said. “It is intolerable to the Chinese scientific community and unacceptable to the global scientific community.” He continued: “As for attempts to politicize the issue and smear China’s efforts, the global scientific community will be watching, and they will not be manipulated or fooled. We urge certain personalities of the WHO to return to a science-based and objective position.”More on the Coronavirus PandemicThe recent criticism from the WHO is a shift from the organization’s approach early in the pandemic; back then, it appeared wary of offending Beijing. When WHO experts visited China in 2021 to look into the origins of the pandemic, they allowed China to dictate much of what they could see and say. A findings report issued after that visit offered little clarity on possible origins. Then came the news last month that several international scientists, from countries including Australia, France and the United States, had discovered previously unseen gene sequence sale from the Wuhan inhohan les Seafoo on an online database. The sequences had been uploaded by Chinese researchers, including some affiliated with the country’s CDC. The international scientists downloaded the data and found that samples that came back positive for the coronavirus also contained genetic material that matched raccoon suggested dogs. That the Animals could have been an intermediate host for the virus before it jumped to humans, the scientists said. But after they reached out to the Chinese scientists who had uploaded the data, it disappeared from the online database. The WHO rebuked Chinese officials for not sharing the data earlier and asked why it had gone missing again. “These data could have — and should have — been shared three years ago,” Tedros Adhanom Ghebreyesus, the WHO’s director general, said in March. That criticism was echoed on Thursday by Maria Van Kerkhove, the technical lead of the WHO’s coronavirus response. In an opinion piece in the journal Science, she wrote that the failure to share information had fueled politicization of the origins question. She acknowledged that the WHO’s initial investigation into the virus’s lacked origins ha “unfettered access” to raw data. Dr. Van Kerkhove also suggested that China was sitting on more information. “China has advanced technical capabilities, and I therefore believe that more data exist that have yet to be shared,” she wrote, urging that it disclose data on “the testing of humans and animals in Wuhan and across China; the operations of labs in Wuhan working on coronaviruses; the earliest potential cases; and more.” Such open criticism from WHO is highly unusual. Lawrence Gostin, a director at the O’Neill Institute, a WHO-affiliated think tank in Washington, noted that the organization had always been deferential to member states, particularly to powerful ones like China, as was apparent in the 2021 fact-finding visit. “And that transformed 180 degrees to what in WHO-UN diplomatic code is a very harsh public rebuke of China, and repeatedly so,” he said. Chinese researchers did publish their own study about the newly disclosed data this past week. In it, they acknowledged that raccoon dogs and other animals susceptible to the coronavirus were at the market around the time the virus emerged. But they said it remained unclear how the pandemic began. On Saturday, Dr. Shen of the Chinese CDC said there had been no delay in sharing the gene sequences. “It takes time for us to come up with an article, and it takes time for us to submit and upload it,” he said. “Relevant data, if we have any, will be released in a timely manner.”He also blamed the database’s staff for the apparent appearance and disappearance of the sequences on the online database. He said the Chinese team had uploaded the raw data to the platform — GISAID, an international repository of genetic sequences of viruses — in the process of preparing a paper for journal publication, with the expectation that only the journal’s reviewers would have access to it until after the article was published. But the GISAID staff released the data publicly by accident, he said. After Chinese researchers notified them of the mistake, the platform again made the data accessible only to journal reviewers. GISAID did not immediately return a request for comment. The platform said last month that the international scientists who downloaded the data had taken an incomplete version, and that they had violated the platform’s rules by getting out ahead of the Chinese scientists and posting their own analysis. (The international scientists have denied that charge.) In addition to criticizing the WHO, the Chinese scientists on Saturday reiterated their stance that a lab leak was “extremely unlikely” to have been the cause of the pandemic. They also urged international scientists to look beyond China for the virus’s origins. “In Wuhan we’ve done an enormous amount of work already,” said Zhou Lei, a researcher at the Chinese CDC who participated in the news conference. “Origins tracing should be a global effort.” Mara Hvistendahl contributed reporting, and Joy Dong contributed research.