KUNMING, April 26 (Xinhua) -- The 81st Mekong River joint patrol led by China, Laos, Myanmar and Thailand concluded Friday noon at Guanlei Port in southwest China's Yunnan Province.

Seven vessels and 134 law enforcement officials from the four countries participated in the mission, which covered more than 514 km in four days.

The patrol involved inspections, a crackdown on drug crime and an anti-drug publicity campaign, according to the provincial public security department.

The patrol also busted a case of illegal possession of homemade bombs and arrested 3 suspects.

China and Laos will conduct a one-week joint training of vessels in key waters after the patrol.

The joint patrols started in December 2011 after a gang hijacked two cargo ships and killed 13 Chinese sailors in Thai waters on Oct. 5 that year.

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.