The Macao Special Administrative Region (SAR) on Tuesday reported four new COVID-19 cases, according to the Novel Coronavirus Response and Coordination Center of Macao.

Two of the cases, both Macao residents, tested positive on Monday in Zhuhai of neighboring Guangdong Province. The health authority in Macao later tested them and their two children, which all came out positive, according to the center.

They were confirmed to have infected the Delta variant of COVID-19, the center said.

One of the four confirmed cases, the daughter in the family, left Zhuhai for Xi'an in northwest China's Shaanxi Province on July 19, boarding a plane which was related to two previously confirmed cases reported in Zhuhai and Zhongshan of Guangdong Province respectively, which could be the source of the infections within the family, the center said.

Starting 9:00 a.m. local time Wednesday, all Macao residents will be required to take nucleic acid tests. The mass testing is expected to be completed within three days, the center said.

Starting 3:30 p.m. Tuesday, all those who need to leave Macao are required to present negative nucleic acid test reports effective within 24 hours, the Macao SAR government announced.

Prior to Tuesday's new cases, Macao had reported a total of 59 confirmed cases, with 57 being imported and two being related to imported cases.