Kan mulls countermeasures if China begins drilling in gas field

Possible countermeasures include a plan for Japan to conduct its own test drilling in the sea near the Chinese offshore facility under development at the gas field, over which both Tokyo and Beijing have claimed exploration rights, the sources said.

The move comes after aerial photographs taken by Japan's Self-Defense Forces showed that China had recently transported what appears to be drilling equipment to the facility in the gas field, known in Japan as Shirakaba and in China as Chunxiao, according to the sources.

Kan met with Foreign Minister Seiji Maehara, Chief Cabinet Secretary Yoshito Sengoku and other officials at his official residence Saturday to discuss how Japan would react if Chinese gas extraction work is confirmed.

They reaffirmed that the Japanese government will continue to pay close attention to China's moves and urge Beijing to exercise self-restraint through diplomatic channels, the sources said.

Japan plans to reinforce surveillance by the Maritime Self-Defense Force's P-3C patrol aircraft in the area around the gas field, they said.

The meeting was also attended by Vice Foreign Minister Kenichiro Sasae, Akitaka Saiki, director general of the Foreign Ministry's Asian and Oceanian Affairs Bureau, and Tetsuhiro Hosono, director general of the Natural Resources and Energy Agency.

The development comes as the two countries are in a dispute over the arrest and indictment of a Chinese captain after his fishing boat collided with Japan Coast Guard patrol boats earlier this month near islands administered by Japan and claimed by China in the East China Sea.