China has reopened a busy checkpoint on its border with Vietnam after a three-week closure over Covid-19 concerns, which had left thousands of trucks stranded and drawn criticism from Hanoi. Cargo and traveller clearance in the coastal border city of Dongxing – bordering Mong Cai in Vietnam – resumed on Monday, the local pandemic control office said. It added that China still required arrivals from Vietnam to show a vaccination certificate and a negative Covid-19 test result from within the previous seven days. Border clearance had also resumed on January 1 at the Friendship Pass in Pingxiang, and six days later at the Longbang and Pingmeng checkpoints in Baise, according to Vietnam News Agency (VNA). The Chinese authorities had stepped up border controls in Dongxing since December 21 after the city reported one Covid-19 infection in routine tests. Under the country’s zero-Covid approach to infections, restrictions on movement and mass testing are used to try to stop the spread of cases as soon as any are found. Dongxing’s 210,000 residents were ordered to stay at home, while clearing of travellers and cargo was suspended. According to the city’s pandemic control office, local authorities had held “multiple rounds of coordination and communication” with their counterparts in Mong Cai since January 3. “The two sides have agreed on the clearance procedures and pandemic control standards for the entry and exit of people, vehicles and goods,” the office said. The Vietnamese Ministry of Industry and Trade said that goods, particularly farm and frozen products, would be given priority to cross the border. “As the pandemic is raging worldwide, customs clearance at all border gates will continue to be tightened,” it said. “Customs processing will therefore not return to the normal rate in the near future.” Vietnamese Deputy Prime Minister Le Van Thanh also urged local authorities to work with the Chinese side to speed up customs clearance to ease the congestion of cargo trucks before the Lunar New Year starts in early February, VNA reported. The Chinese border controls have drawn criticism from Vietnam as it struggles to get its export-oriented economy back on track. In a blow to Vietnamese fruit farmers, China imposed a four-week ban on dragon fruit imports from Vietnam until January 26 after health authorities in Shanxi and Zhejiang provinces said they had found the coronavirus on packaging from the country. Control measures were last month described by Vietnam’s trade ministry as “overkill” and a cause of “great losses” to bilateral trade, after a video call with officials from Dongxing’s provincial-level authority of Guangxi Zhuang autonomous region. China is Vietnam’s largest trading partner and the largest market for Vietnam’s fruit and vegetables. According to the Vietnamese government, as of Saturday, more than 3,600 cargo trucks, most carrying fruit and farm products, were stuck at border checkpoints. The border controls have also ignited discussion in Vietnam over whether the country should step up efforts to diversify its exports, which are heavily reliant on China. Chinese foreign ministry spokesman Wang Wenbing last week said that the measures China had taken were “necessary” and that the Chinese market was open “to all countries”.