BEIJING (REUTERS) - China reported 68 new coronavirus cases for July 27, up for the fourth consecutive day, including two in Beijing, the country's health authority said on Tuesday.

China is battling the most aggressive return of Covid-19 in months, driven by infections in the far western region of Xinjiang and a separate flare-up in the northeast.

Of the new local infections for July 27, 57 were in Xinjiang, according to a statement by the National Health Commission.

That brings the total number of cases in the region's current outbreak to 235 since the first infection was reported on July 16.

Xinjiang has yet to explain how patient zero, a 24-year-old woman who worked in a mall in its capital Urumqi, contracted the virus.

The northeastern province of Liaoning reported six new cases as of July 27. The current outbreak in Liaoning, which began on July 22, centred mostly on the port city of Dalian, east of Beijing.

The first case in Dalian worked at a seafood processing company, and had not travelled out of the city in recent weeks.

To contain the spread of the virus, Xinjiang and Dalian have tested millions of people for Covid-19, but the coronavirus is already on the move.

Beijing reported two new infections, one linked to Dalian and the other imported. They were the first new cases in the Chinese capital for more than three weeks.

On Monday, the northeastern province of Jilin reported two new cases, its first infections since May. Both were staff at the Dalian seafood processing company, and had travelled back to Jilin from nearby Dalian about 10 days ago.

As of Monday, mainland China had 83,959 confirmed coronavirus cases, the health authority said. The Covid-19 death toll remained at 4,634.