China on Saturday demanded an apology and compensation from Japan over the detention of its fishing boat captain seized near disputed waters, Chinese state media reported.
Zhan Qixiong was detained earlier this month after his trawler collided with Japanese vessels near disputed islands in the East China Sea.
He was accused of obstructing Japanese public officers while they performed their duties.
Zhan was freed Friday, and arrived home safely a day later in southeast China's Fujian province, according to Xinhua news agency.
"We decided to suspend the charges in consideration of the Japan-China relationship," the Japanese prosecutor in the case said.
However, Beijing decried the arrest, and accused Japan of illegally arresting the captain and his crew of 14, according to Xinhua.
China considers the Diaoyu Islands and most of the South China its property, disputing neighboring countries' claims.
In Japan, the islands are known as the Senkaku. The clash over territorial waters and islands -- and the natural resources that go with them -- is a flash point in the Asia-Pacific region.
Word of the captain's release quickly followed the arrest of four Japanese nationals in China.
The four are being investigated for entering a military zone without authorization and videotaping military targets, Chinese state media said.
Neither country linked the captain's case with the arrest of the four Japanese nationals, however.
After Zhan's release, the Chinese Foreign Ministry said in a statement that the detention was "unlawful and invalid," demanding an apology and compensation, Xinhua said.
China said the two sides should resolve the problems through dialogue and consultation.