China released a circular on Thursday requiring a reduction in the unnecessary movement of people in medium－and high-risk areas, as well as the avoidance of gatherings.

People in medium－and high-risk regions who wish to travel to a different region should hold certificates or green health codes that can prove negative nucleic acid test results, or they must undergo nucleic acid testing or a 14-day supervised quarantine immediately upon arrival, said the circular issued by the State Council joint prevention and control mechanism against COVID-19.

People in low-risk areas are allowed to travel freely with a green health code, a normal body temperature and personal protection, the circular said, adding that people from low-risk areas should avoid visiting medium－and high-risk areas if it's not necessary.

The circular urged all localities to rectify any unreasonable restrictions in addition to regular prevention and control measures.

Since May, China has eased its domestic travel restrictions after seeing a significant drop of new locally-transmitted infections.

Chinese authorities also standardized the health QR code for COVID-19 nationwide, enabling citizens who carry a green code－meaning they are healthy－to travel freely across the country.

However, the relaxation came to a halt when Beijing reported a new coronavirus outbreak in mid-June linked to a local food market. The city had previously gone 56 days without a locally transmitted case.

Beijing authorities have tightened the lockdown, and from June 16 people in medium－and high-risk areas of Beijing have been prohibited from leaving the city, and those in other areas who do need to leave the city must have a negative test result.

On Thursday, the Chinese mainland reported 13 new cases, including 11 domestically transmitted cases in Beijing and two imported cases reported in Shanghai, the National Health Commission said on Friday.

The capital city reported 280 domestically infected cases from June 11 to 26.

The total number of imported cases reached 1,895 by the end of Thursday. Among them, 1,811 have been discharged from hospitals and no deaths had been reported.

By the end of Thursday, the Chinese mainland had reported 83,462 COVID-19 cases. Hong Kong, Macao and Taiwan have reported 1,686 cases.

Xinhua contributed to this story.