UPDATE 1-Mainland China reports 15 new coronavirus cases vs 28 previous day

(Addd city-wide testing in Kashgar)

BEIJING, Oct 25 (Reuters) - China on Sunday reported 15 new coronavirus cases in the mainland, down from 28 cases the previous day, the health commission said on Sunday.

All 15 of the new infections reported for Saturday were imported, according to a statement by the National Health Commission. It reported 19 new asymptomatic patients, compared with 27 a day earlier.

The health commission in China's northwestern region Xinjiang said on Saturday that one local asymptomatic case was detected in Kashgar city, China's first local detected case since Oct. 14.

All close contacts of the patient have been isolated for medical observation and local authorities are carrying out epidemiological investigations, the Xinjiang commission said in a statement.

Kashgar has launched a city-wide nucleic acid test covering the city's 700,000 people. As of Sunday morning, more than 300,000 people had been tested and the rest would be covered within two days, the city government said in a statement.

As of Saturday, mainland China had 85,790 confirmed coronavirus cases, the health authority said. The COVID-19 death toll stands at 4,634. (Reporting by Muyu Xu, Shen Yan and Ryan Woo; Editing by Lincoln Feast and William Mallard)