Chinese officials didn’t warn the Chinese public it was likely facing a pandemic from the novel coronavirus for six days after they reached that conclusion themselves, the Associated Press reports. In that crucial time period, the city of Wuhan hosted a mass banquet for tens of thousands of people and millions began traveling for Lunar New Year celebrations. At the time, Chinese health authorities were issuing instructions to provincial health officials, ordering them to identify suspected cases, open fever clinics, and tell doctors and nurses to don protective gear—but they were marked “internal” and “not to be publicly disclosed.” A memo obtained by the AP shows that the head of China’s National Health Commission, Ma Xiaowei, laid out a grim assessment of the situation on Jan. 14 in a confidential teleconference with health officials, and another call was held to convey instructions on the virus from President Xi Jinping. Under a section titled “sober understanding of the situation,” the memo said that “clustered cases suggest that human-to-human transmission is possible.” The Chinese government has denied suppressing information in the early days, saying it immediately reported the outbreak to the World Health Organization.