Tokyo, Japan (CNN) -- Four Japanese nationals have been arrested in China, and are being investigated for entering a military zone without authorization and videotaping military targets, Chinese state media said.
The arrests come amid the two nations' diplomatic battle over Japan's detainment of a Chinese fishing captain.
"We believe if our employees knew about the area being off-limits, or the regulation that prohibited cameras in the location, they would not have taken such action," the company's executive director said at a news conference Friday in Tokyo.
The four Japanese nationals were sent to China for a Japanese government project to reclaim World War II chemical weapons left by Japan's Imperial Army, their company said Friday. A Chinese national also is missing and presumed arrested with his Japanese co-workers on Wednesday in in northern Hebei Province.
They work for Fujita Corp., a mid-size Japanese construction company that Goldman Sachs Group acquired in April 2009.
CNN
