The men were among 37 fishermen detained by Chinese patrols last month for allegedly violating China's fishing ban near the disputed Paracel islands. The largely uninhabited islands in the South China Sea, claimed by both Vietnam and China, straddle busy sea lanes.

China decided to fine the fishermen 210,000 Chinese yuan ($31,000) and released 25 of them. Authorities continued to hold the remaining 12 until the fines are paid.

Vietnamese authorities refuse to pay and have been demanding the fishermen's immediate release, government spokesman Le Dung told reporters at a regular press conference. He said the men were detained while fishing in sea areas under Vietnamese sovereignty.

Vietnam also requests that China "compensate losses in health and property of the detained fishermen," he said.

China imposed a fishing ban on some parts of the South China Sea in May, saying it was to prevent depletion of seafood resources. The ban lasts until August 1.

The Associated Press - July 11, 2009