Law-enforcement authorities from China, Laos, Myanmar and Thailand joined forces on Tuesday for the start of the 97th Mekong River joint patrol.

Three Chinese vessels departed from Jingha Port, Xishuangbanna Dai Autonomous Prefecture, in southwest China's Yunnan Province, while a Laotian vessel departed from the Ban Mom Port in Laos, with the patrol due to last several days.

Before the patrol, law-enforcement authorities of the four countries held a video conference to discuss the security situation of the river and reached an agreement on jointly cracking down on illegal activities and fighting against COVID-19.

The Mekong River, known as the Lancang River in China, is a vital waterway for cross-border shipping.

China, Laos, Myanmar and Thailand have been carrying out joint patrols on the Mekong River for eight years.