From Peering Into The Interior blog:
According to Sina’s Pioneer magazine ( ÂõΩÈôÖÂÖàÈ©±ÂغÊä•) and China’s Maritime Department, the United States has on several occasions (cited as 2002, 2003, 2004, and 2005) “illegally entered” China’s maritime territory to conduct maritime surveillance.
The sina article states that:
“When America engages in military surveying, on the one hand it’s for helping the American military familiarize with the “battlefield environment,” yet at the same time they are conducting surveillance, such as monitoring China’s naval activities in maritime territory China has direct jurisdiction over(ÁÆ°Ëæñʵ∑Âüü). This clearly is an extreme threat to China’s maritime security.” (ËøôÊòæÁÑ∂ÊòØÂØπ‰∏≠ÂõΩʵ∑Ê¥ãÂÆâÂÖ®ÁöÑÊûŧ߮ÅËÉÅ) [Full Text]
