Phan Hong Tien, head of the Dong Dang Border Gate Economic Zone management board, said most of the containers carry fruits and agriculture produce, and the delay could result in heavy damage for farmers and traders.

The piling up of thousands of containers has happened after China imposed more stringent import measures earlier this month. Tien said China only allows trade via five border gates in the province, compared to 12 before, and each of them is open for only five hours a day, compared to 9-10 hours before.

Around 300 containers pass through these gates a day, compared to 1,200 in March, he added.

Lang Son authorities have proposed that China opens its gates for the same duration as before, but this has been rejected.

The  province has set up a team of 600 drivers at two border gates since April 7 to facilitate border transport. Wearing protective gear, they will drive container trucks through the border and return to quarantine camps to save other drivers from being quarantined for 14 days after returning from China.

First quarter fruit exports to China, the largest buyer of Vietnamese agriculture produce, fell 29.4 percent year-on-year to $300 million as the Covid-19 pandemic halted normal trade, according to the Ministry of Agriculture and Rural Development.