Japan is to release a Chinese fishing boat captain whose arrest two weeks ago led to the worst row with Beijing in years, Japanese media report.
The Japanese authorities had accused Zhan Qixiong of deliberately ramming two patrol vessels near disputed islands in the East China Sea.
China had been demanding his immediate and unconditional release.
The move came after four Japanese men were detained in China on suspicion of illegally filming in a military area.
A Japanese foreign ministry spokesman said its embassy in Beijing had received confirmation that the four were being held, but he said he did not want to speculate whether it was linked to Japan's detention of a Chinese fishing boat captain.
Officials said the four men were employees of a Japanese construction company who were in China to bid for a project to dispose of chemical weapons from World War II.

BEIJING: A torrent of floods caused by heavy storms have killed 115 people in southern China, with 21 people still missing as weather reports show rains beginning to subside.Emergency rescue teams have been dispatched across southern China to help the 685,000 people evacuated as a result of the flooding, which has caused £1.53 billion in damages, a statement on the Ministry of Civil Affairs website said.But one official said the worst may be over."The rain was pretty severe earlier, but now the weather is improving," said the official surnamed Chen who answered the phone at the Hunan Water Bureau information office. Like many Chinese officials he would give only his surname.China's rainy season, which began this month, follows the worst drought in a century for southern China's Yunnan, Guizhou, Guangxi regions.The drought affected 61 million people, leaving millions without drinking water and 12 million acres barren since last year.The floods hit 13 provinces, including Guangdong, Sichuan and Zhejiang, and damaged more than 80,000 homes and affected more than 10 million people, said a statement posted on the State Flood Control and Disaster Relief Headquarters website.China's huge land mass means severe storms can cause floods in one region, while other parts of the country can experience drought.