Beijing on Wednesday recorded its first new cases of the Chinese coronavirus since January as Chinese health officials said a recent outbreak of the disease in eastern China’s Nanjing city continues to spread nationwide, China’s state-run Global Times reported.

“The two patients, who are a couple, had both traveled to Zhangjiajie, [located in] China’s Hunan Province, which has become a new hotspot in the latest outbreak,” according to the newspaper.

“The couple returned to Beijing from their trip on Sunday [July 25] on a high-speed train and spent around one hour on three metro lines on their way back home in Changping district,” the Global Times detailed.

The couple then tested positive for the Chinese coronavirus on Wednesday, July 28, “both with mild symptoms. All 654 people who had contact with the couple have been put under medical observations,” the newspaper revealed.

The residential community in which the couple resides “and nine neighboring communities, with a total of around 41,000 residents, have been sealed off,” Tong Lizhi, vice head of Changping district, told reporters on July 29.

The safety of Changping district is especially important to Chinese government officials as it serves as the site for Beijing’s Future Science City, a “technological innovation hub, hosting dozens of corporate R&D [Research & Development] centres spread over 43.5 square kilometres [16.8 square miles],” according to Nature.

Beijing’s new coronavirus cluster infection is linked to China’s latest major epidemic of the disease in Nanjing, capital of eastern China’s Jiangsu province. Nanjing health officials first detected the city’s coronavirus outbreak on July 20 after nine staff members of the Nanjing Lukou International Airport tested positive for the Chinese coronavirus. The outbreak has since spread throughout Nanjing and beyond the city via its airport to at least 13 other Chinese cities — including Beijing, Chengdu, and Dalian —  across five provinces.

Beijing is China’s national capital city and is located within northern Hebei province. Chengdu is the capital of southwestern Sichuan province. Dalian is a major port city in northeastern Liaoning province, which borders North Korea. As mentioned by the Global Times, China’s southern Hunan province has also detected new coronavirus cases linked to Nanjing’s outbreak in recent days.

“Hulun Buir in North China’s Inner Mongolia [has] also released epidemiological investigation results of some close contacts of cases confirmed in Nanjing,” the Global Times revealed Thursday. In the same report, the Chinese Communist Party mouthpiece called Nanjing’s coronavirus epidemic “the most extensive domestic contagion after Wuhan.”

Central China’s Wuhan city was the first location on earth to report cases of the then-novel coronavirus in late 2019. The city’s outbreak spread throughout China and then to the rest of the world, resulting in the ongoing Chinese coronavirus pandemic.

Nanjing reported 13 new cases of the Chinese coronavirus on July 29, increasing the city’s total number of infections to 184. Nanjing is a mega-city with a population of more than 9.3 million. It is located 185 miles northwest of Shanghai, the most populous city proper in the world.