A Chinese fishing boat and its crew of nine were detained by an Indonesian gunship Tuesday in the South China Sea, police said Wednesday.

The ship, registered to south China's Guangxi Zhuang Autonomous Region, was seized by the Indonesian patrol boat at 4:58 p.m. in waters near the Nansha Islands, said Qin Yongjun, spokesman with Guangxi's public security department.

After negotiations, the boat was released at 6:42 p.m. Tuesday.

However, eight fishermen who had been taken aboard the Indonesian ship were injured, with one seriously, Qin said.

A preliminary investigation by the region's border defense department showed there might be abuse involved, he said.

Police are investigating the case.