Attacks along the Mekong River after shipping resumed on Dec 10 are occasional and isolated cases, said a senior officer from Southwest China's Yunnan provincial public security department.

Shipping was suspended after 13 Chinese sailors were killed along the river in October.

"We are seeking a variety of modes of cooperation, such as joint patrols, armed escorts, intelligence gathering and sharing with the other three countries, Laos, Myanmar and Thailand, to boost the safeguarding of shipping on the river," said Meng Sutie, director of the Yunnan provincial public security department.

The four countries have also taken the initiative in attacking armed factions and drug gangs that have been targeting Chinese cargo ships in the Mekong River's Golden Triangle region, Meng told China Daily on the sidelines of the annual session of the National People's Congress.

The Mekong River is surrounded by high mountains and dense forests, and in some areas the watersheds are complex and turbulent, said Dai Peng, director of the criminal investigation department under the Chinese People's Public Security University.

"Some armed criminals have taken this chance to hide themselves and launch sudden attacks on Chinese cargo ships using motorboats," Dai said.

"Meanwhile, the Mekong watershed is at the junction of the four countries, and river shipping is under their separate jurisdictions, so it's inevitable to have safety management loopholes," Dai said.

Attacks are still possible in the future, Meng said, though not as frequently as before.

Two attacks targeting Chinese vessels since international shipping traffic was fully restored on Dec 10 have made headlines, raising safety concerns about the river.

On Jan 4, four Chinese cargo ships and a Myanmar patrol boat were attacked in the early morning at Wan Pung Port in Myanmar.

According to Thai naval police, the attackers fired two rockets. One fell into the water and the other exploded near the ships. No casualties or damage to the vessels were reported.

Ten days later, another Chinese commercial vessel was attacked by unidentified gunmen in the Golden Triangle region. Although the five crewmen on board were uninjured, bullet holes could be seen in the windows, walls and doors of the vessel.

"They are just isolated cases rather than planned and premeditated attacks," Meng said.

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Li Yingqing contributed to this story.