Tokyo, Japan (CNN) -- Japan on Monday released 14 crew members of a fishing trawler that crashed into two Japanese patrol boats last week, but the captain remains in custody, officials said.
The arrests off the disputed Diaoyu Islands, in the East China Sea, had angered China. Beijing had repeatedly summoned the Japanese ambassador, demanding the fishermen's release.
Beijing says the Diaoyu Islands and most of the South China Sea belong to China, disputing neighboring countries' claims.
The clash over territorial waters and islands -- and the natural resources that go with them -- is a flashpoint in the Asia-Pacific region.
The Japanese coast guard freed the 14 crew members after completing an investigation, a coast guard official told CNN.
The 14 were to fly back to China on Monday morning, according to Chinese state media. No release date was given for the captain, whom Japanese authorities have accused of obstructing public officers while they performed duties.
"China will never accept the Japanese side's applying domestic law to the Chinese fishing boat operating in that area," said Chinese Foreign Ministry spokeswoman Jiang Yu, according to the Xinhua news agency.
Jiang also said in a written statement that Japan's investigation was illegal, invalid and conducted in vain, Xinhua reported.
CNN's Junko Ogura in Tokyo, Japan, and Steven Jiang in Beijing, China, contributed to this report.