The 91st Mekong River joint patrol led by China, Laos, Myanmar and Thailand began Tuesday, as three Chinese vessels left the Guanlei Port in southwest China's Yunnan Province.

In a bid to safeguard the security and stability along the Mekong River, the four countries will carry out joint visits, inspections and an anti-drug publicity campaign during the four-day patrol, according to the Yunnan provincial department of public security.

The mission will cover areas including the "Golden Triangle," an area notorious for drug production, with five vessels in participation.

Affected by the coronavirus epidemic, law enforcement authorities of the four countries will jointly direct the operation by remote video command system for the first time.

A remote video conference was held by the four sides before the patrol to share information.

The law enforcement will send a publicity team to promote knowledge about the epidemic prevention and control.

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.