Law-enforcement authorities from China, Laos, Myanmar, and Thailand joined forces on Tuesday for the 113th Mekong River joint patrol.
Two Chinese vessels departed at 9:00 a.m. on Tuesday from Jingha Port in Xishuangbanna Dai Autonomous Prefecture, southwest China's Yunnan Province, for the patrol, said the Yunnan provincial public security department.
The vessels will navigate over 600 km in four days and three nights in the joint operation.
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.