Law-enforcement authorities from China, Laos, Myanmar and Thailand joined forces on Tuesday to start the 117th Mekong River joint patrol.

Two Chinese vessels departed at 9 a.m. from Jingha Port, Xishuangbanna Dai Autonomous Prefecture, southwest China's Yunnan Province, according to the provincial public security department.

During the patrol, the four countries will carry out non-contact operations to safeguard safety and stability along the river basin.

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 conducting joint patrols on the river dating back to December 2011.