KUNMING, June 29 -- Law-enforcement authorities from China, Laos, Myanmar, and Thailand joined forces on Wednesday to begin the 130th Mekong River joint patrol.

Seven vessels participating in the operation departed from three ports in China and Laos, said public security authorities in southwest China's Yunnan Province.

The patrol is also scheduled to carry out anti-drug publicity activities themed on the International Day against Drug Abuse and Illicit Trafficking, which falls on June 26, along the river.

The Mekong River -- known as the Lancang River in China -- is a vital waterway for cross-border shipping. The four countries have been conducting joint patrols on the river since December 2011.