China National Offshore Oil Corp (CNOOC) said Saturday gas production had begun from an oil and gas field in the East China Sea, a territory that is the focus of a drawn-out dispute with Japan.
On an inspection tour at the Chunxiao field last month, a senior government official said the first stage of gas production had begun and urged CNOOC to make good use of its resources, the company's website reported.
"The first phase of Chunxiao oil and gas field has already entered the production stage," Zhang Guobao, vice director of the National Development and Reform Commission, was quoted by the website as saying.
"But inadequate gas usage from downstream users has limited the speed of the oil field's exploration," he added.
Japan and China have long disputed the maritime boundary that lies between them, and Beijing has always insisted its explorations in the East China Sea are within China's territorial waters.
But Japan says the gas field lies too close to its Exclusive Economic Zone (EEZ) — a delineation not recognized by China — and fears China might siphon off resources from an area Japan claims as its territory.
The Japanese foreign ministry could not be reached for comment on Saturday.
But Japanese business daily Nihon Keizai Shimbun quoted unnamed foreign ministry sources as saying that Japan has started examining counter-measures against China's development of a gas field.
If gas production at Chunxiao is confirmed, Japan will officially protest against China and call for an immediate halt of drilling, it said.
Japan would try to resolve the dispute through dialogue but would step up its measures if Beijing denies its request, the report added.
A 1999 Japanese survey estimated there were 200 billion cubic meters (seven trillion cubic feet) of gas reserves in the area, which is some 400 kilometers (250 miles) northwest of the Japanese island of Okinawa.
Tensions escalated between the two countries last year after Japan said it had spotted flames indicating China had started production close to the area where Japan claims development rights. China began test-drilling in 2003.
The two countries failed to find common ground during many rounds of talks, with China saying "great differences still remained" after the last round in July.
The energy reserves are among a number of disputes that have badly damaged relations between the Asian powers. They are also divided by the legacy of Japan's wartime militarism in the region.
