Despite the difficulties he faces, Yan said he does the job out of a love for his country. "The best thing for me is taking a hot shower at ports of call. It feels really great," he said.

During a videoconference early last month to mark the 10th anniversary of the joint missions, officials and police from the four countries approved a plan for patrol and law enforcement, vessel maintenance and joint training.

They agreed that security on the Mekong had significantly improved, although crimes involving drugs, gambling and internet fraud still pose challenges.

Strengthened cooperation is needed on exchanging information, marine skills, maintaining equipment, and controlling the pandemic, they said.

Such action would help prevent cross-border crimes, promote environmental protection and anti-terrorism measures, safeguard information security, and contribute to the Belt and Road Initiative, the participants added.