Officials in the northwestern Chinese city of Xian are facing punishment after a Covid-19 outbreak led to the lockdown of its 13 million residents, authorities said on Friday, as the number of new cases declined.

All domestic flights out of Xian and most trains originating from the city scheduled for Friday were cancelled. Officials in Xian, which is famed for its terracotta warriors buried with China’s first emperor, say the outbreak has been traced to the arrival of a plane from Pakistan.

The Central Commission for Discipline Inspection said in a statement that 26 people in Xian were being held accountable for “not doing a good job” in their Covid-19 prevention and control effort, but did not specify their punishment.

New locally transmitted cases with confirmed symptoms in the city fell to 49 for December 23, down from 63 a day earlier, the first decline since December 10. Since Thursday, each Xian household has been limited to sending only one person to shop for necessities every two days, while others may not leave unless they have essential jobs.