The 109th joint Mekong River patrol by China, Laos, Myanmar, and Thailand concluded on Friday, with three Chinese law-enforcement vessels returning home to a port in southwest China's Yunnan Province.

The joint patrol, with five vessels, navigated more than 500 km over four days and three nights, the Yunnan provincial public security department said.

The patrol followed relevant protocols on COVID-19 prevention and control and targeted cross-border crimes and illegal activities in the Mekong River basin.

The Mekong River, or 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 since December 2011.