HANOI, Vietnam — Chinese patrol ships arrested six Vietnamese fishermen in waters off China's Hainan Island, officials said Friday, an incident likely to heighten tensions between the nations as they spar over a territorial dispute.
Chinese Foreign Ministry spokesman Hong Lei said the arrests occurred Thursday 8 miles (12 kilometers) off the island, a location that would place the fisherman within China's territorial waters.
However, Nguyen Ky, an official in the district where the fishermen came from, said the arrests took place in disputed waters near the Gulf of Tonkin, which lies off Hainan. He said his information came from fishermen in a second boat that was briefly detained and reported the incident via radio.
Lei said Chinese authorities were handling the situation "according to the law" and urged Vietnam to "strengthen control over their fishermen .... and prevent similar incidents from happening again."
Vietnam's Ministry of Foreign Affairs didn't immediately return calls seeking comment.
Vietnamese fishermen have been detained by China before, but this is the first time since China deployed a large oil rig in early May close to the disputed Paracel Islands, causing a dangerous spike in tensions between the two nations.
Hanoi protested the deployment and sent coastal patrol ships to try to force away the rig, which is protected by a large flotilla of Chinese ships. The Vietnamese ships have been unable to get close to the rig, and dozens have been damaged in collisions with larger, stronger Chinese vessels, according to Vietnamese officials.
China has increasingly sought to enforce its claims to disputed territories in the region as its military and economic strength have grown.
The territorial disputes are also causing tensions with the Philippines and Japan and prompting increased spending on military hardware.
Vietnam's government said Thursday it plans to spend US$540 million on 32 new coast guard and fishery patrol vessels to boost its maritime muscle and surveillance capacities.