Dalian, Liaoning province, reported three new locally transmitted asymptomatic COVID-19 cases on Monday, officials announced at a news conference on Monday night.

While screening those who arrived in the port city by passing the Lukou International Airport in Nanjing, Jiangsu province, three were found positive for nucleic acid tests, said Zhao Lian, deputy director of Dalian's health commission.

They were confirmed to be asymptomatic carriers by the municipal medical treatment expert team and have been transferred to a designated hospital for quarantine and medical observation, said Zhao.

The three flew to Zhangjiajie, Hunan province, via Nanjing on July 17. They stayed at Lukou airport for around two hours for flight transfer. On July 24, they flew from Tongren, Guizhou province, via Xi'an,Shaanxi province and arrived in Dalian the next day.

Zhao said that Dalian immediately launched the emergency plan, and promptly carried out epidemiological investigation, close contact screening, nucleic acid testing, as well as control and disinfection of key sites.

The city also strengthened screening work on those who came or returned Dalian from Nanjing.

As of 4 pm on Monday, 10,417 people from Nanjing have been identified for 14-day quarantine and four times of nucleic acid tests. By 9 pm on Monday, all nucleic acid tests have been negative.