All 12 million residents of Wuhan, Hubei province, will be tested for novel coronavirus after a new cluster was detected in the Chinese city hardest hit by COVID-19 last year.

Control and prevention measures were reactivated in Wuhan on Aug 3 following the confirmation of three locally transmitted cases on Aug 2. They are the first cases detected in the city since June last year.

Wuhan authorities have decided to launch citywide nucleic acid testing immediately, Li Tao, deputy secretary-general of the city government, said at a news conference.

"Comprehensive screening can effectively block possible sources of infection and eliminate hidden dangers," Li said.

Since July 31, Hubei has reported six confirmed locally transmitted cases, and eight asymptomatic carriers, according to data from the provincial health authority.

One of the three infected people, surnamed Tang, came into contact with a tour group from Huai'an, Jiangsu province, in the waiting hall of Jingzhou Railway Station in Jingzhou, Hubei, on July 27.

The other two patients are close contacts of Tang, said Li Yang, deputy director of the Hubei Provincial Center for Disease Control and Prevention, on Aug 3.

The three patients are all infected with the Delta variant. The three cases are related to the Huai'an ones, according to results of epidemiological survey and gene sequencing, Li said.

The Huai'an tour group had visited an outbreak hot spot, Zhangjiajie, Hunan province, before their short stay in Jingzhou Railway Station. Several people in the group have tested positive for COVID-19.

The three Wuhan patients, as well as one from Huanggang and two in Jingzhou, are at a designated COVID-19 hospital for medical treatment, Liu Dongru, deputy director of the Hubei Health Commission said at a news conference on Aug 3.

They are all in a stable condition. Liu said virus prevention and control measures have been activated at all levels in Wuhan to prevent the spread of the virus.

Restrictions have been imposed on traffic and public transportation in the city.
Twenty-three bus lines had been suspended by 10 am on Aug 3. Bus service to provinces including Jiangsu, Hunan and Henan, which have reported outbreaks in recent days, has been suspended, as has service at some subway stops in the city.

Shows and performances at scenic areas in Wuhan were also suspended as of Aug 3 and summer classes at training centers canceled.

Supplies of daily necessities, including rice, flour, meat, eggs, vegetables and milk, are abundant and prices are stable, the city's commerce bureau said.

All outlets of the 13 major supermarkets as well as over 400 gas stations are operating as usual, the bureau added.

"We have increased supplies to the stores around the closed residential communities. If there is any store running out of stock we can replenish it within two to three hours," said a staff member at Zhongbai Holdings Group, a retail outlet chain operator, in Wuhan.

Wuhan resident He Zhiqiang said, "Stocks of some goods are running out at online platforms, but supplies are ample at supermarkets."