BEIJING -- The Chinese mainland on Sunday reported 21 newly confirmed COVID-19 cases, including six locally transmitted cases and 15 arriving from outside the mainland, the National Health Commission said Monday.

All of the locally transmitted cases were reported in Northeast China's Liaoning province, the commission said in its daily report. No new deaths related to the disease were reported.

A new suspected case arriving from outside the mainland was reported in Shanghai on Sunday, said the commission.

Sixteen COVID-19 patients on the Chinese mainland were discharged from hospitals following recovery on Sunday.

By the end of Sunday, a total of 4,218 imported cases had been reported on the mainland. Among them, 3,948 had been discharged from hospitals following recovery, and 270 remained hospitalized. No deaths had been reported among the imported cases.

The total number of confirmed COVID-19 cases on the mainland reached 86,976 by Sunday, including 339 patients still receiving treatment.

A total of 82,003 patients had been discharged from hospitals following recovery on the mainland, and 4,634 had died as a result of the virus, according to the commission.

There was one suspected COVID-19 case on the mainland on Sunday, and 11,791 close contacts remained under medical observation.