Law-enforcement officers from China, Laos, Myanmar and Thailand will start the 100th Mekong River joint patrol on Tuesday, a police officer in southwest China's Yunnan Province said Sunday.

Over the last nine years, officers from the four countries have jointly patrolled a total of 56,100 km along the river, preventing economic losses valued up to 188 million yuan (28.8 million U.S. dollars) for people from the countrie, Zhou Jianzhong, executive deputy chief of the provincial public security department, told a press conference.

Since the joint patrol mechanism was established, the law-enforcement departments of the four countries have seized over 4,600 kg drugs, rescued 130 commercial vessels from danger and escorted thousands of commercial ships, said Zhou.

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

The Mekong River, with its Chinese stretch known as the Lancang River, is a vital waterway for cross-border shipping among China, Laos, Myanmar, Thailand, Cambodia and Vietnam.