A total of 109 law enforcement officers from the four countries participated in the mission on board five vessels, which navigated 651 km in four days and three nights, according to the provincial public security department.
The top officials of the participating nations were extremely happy with this year's exercise which ended successfully although their countries are currently grappling with the Covid-19 (coronavirus) pandemic.
Chinese and Laos officers also examined 27 vehicles, 42 persons and six tonnes of cargo during joint operations in Laos waters.
Chinese officers also donated masks, protective gowns, gloves and other materials for protection from the COVID-19 disease.
The Mekong River, known as the Lancang River in China, is a vital waterway for cross-border shipping among China, Laos, Myanmar, Thailand, Cambodia and Vietnam.
China, Laos, Myanmar and Thailand have been carrying out joint patrols on the Mekong River for eight years. - Xinhua/Asian News Network