Beijing has tightened Covid-19 curbs over concerns that China’s mass travel during the holiday period could cause cases to spike in the capital, as it reported locally transmitted cases for a fourth straight day, Reuters reports.

A meeting led by the capital’s Communist party boss, Cai Qi, urged all districts in Beijing to enter an “emergency” mode, sealing off residential compounds and villages where infections are found. Beijing has asked its civil servants to stay in the city from Jan 1 until the holiday and asked the public to avoid unnecessary travel during the period.

China’s southern technology hub of Shenzhen reported one asymptomatic case on Sunday, a patient who made two business trips to Beijing this month. Shunyi district, where all of Beijing’s recent coronavirus cases have been reported, has declared a wartime mode and testing for all its 800,000 people. All the cases reported on Saturday were close contacts of previous cases.

Public venues such as theme parks and churches have scaled back operating hours. Some Catholic churches in Beijing, including Wangfujing’s Catholic Church, have stopped admitting churchgoers and halted group activities, the archdiocese of Beijing said on its website.