Beijing, China (CNN) -- Fourteen Chinese fishermen returned home Monday, after being freed by Japan, state-run media reported.
The crewmen and the captain of their fishing trawler were taken into custody last week, after their vessel crashed into two Japanese patrol boats off the disputed Diaoyu Islands, in the East China Sea.
The captain remains in custody. Japanese authorities have accused him of obstructing public officers while they performed duties.
A plane chartered by the Chinese government landed in China's southeast port city of Fuzhou on Monday afternoon, carrying the 14 crewmen, according to the Xinhua news agency.
Their detention had angered Beijing, which 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.
"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 Xinhua.
Jiang also said in a written statement that Japan's investigation was illegal, invalid and conducted in vain, Xinhua reported.
"The captain was still illegally detained by the Japanese side and China strongly demands the Japanese side to immediately let him return," Jiang said, according to Xinhua.
CNN's Junko Ogura in Tokyo, Japan, and Steven Jiang in Beijing, China, contributed to this report.