Zhuhai, Guangdong province, launched a citywide nucleic acid testing campaign on Wednesday and required all cinemas and entertainment venues to temporarily stop business to prevent and control the spread of the novel coronavirus, city authorities said.

All those leaving Zhuhai from its airport, railway stations and bus terminals must show a negative nucleic acid test result less than 48 hours old and a green health code, the city's anti-COVID-19 headquarters said on Wednesday.

All cross-border truck drivers entering and leaving Zhuhai must show a negative nucleic acid test result taken within 12 hours, it said.

The new anti-coronavirus measures were introduced after four Macao residents' nucleic acid test results came back positive on Tuesday. Three of the Macao residents had visited Zhuhai before they tested positive.

Macao has launched a three-day nucleic acid testing campaign for all residents to screen for possible COVID-19 patients and asymptomatic carriers.

The Macao Special Administrative Region government has decided to temporarily close some indoor entertainment venues from Thursday.

In Zhongshan, Guangdong, mass nucleic acid testing has been launched in the townships of Tanzhou, Sanxiang, Shenwan and the Wuguishan neighborhood. They border Zhuhai in the western part of the Pearl River Delta.

On Tuesday, Zhuhai government departments started tracing the activities of the three Macao residents who tested positive after visiting the city.

The departments have also expanded screening at the city's airport, exit and entrance ports and other key venues.

In Guangzhou, capital of Guangdong province, all passengers wanting to travel on the city's public buses must have their temperature taken and show a green health code before boarding.