Japan is warning China not to expand gas exploration in disputed waters of the East China Sea, and sending ships to investigate reports that China is possibly siphoning gas from the seabed beneath waters claimed by Japan.

Tokyo ordered the Japan Oil, Gas and Metals National Corporation (JOGMEC) to put both of its survey ships on standby and to prepare to deploy without any foreign members of staff on board because drilling was detected in the area.  Japan had recently been caught by surprise when Chinese gas and oil companies asked the government for permission to develop seven near energy fields in the disputed waters.

A senior Japanese source said that the ships would operate “right up to the median liner, meaning the disputed maritime boundary with China. 

“If the Chinese side is to proceed unilaterally with development in the area over which there are conflicting claims, Japan would never accept it,” Japanese Chief Cabinet Secretary Yoshihide Suga told a regular news conference on Thursday.

Earlier on Thursday, China’s two top state run newspapers accused Japanese Prime Minister Abe of playing the “China Threat” card to win votes in this weekend’s upper house elections, and accused him of “dangerous politics”.