Japan says China's gas drilling 'regrettable'

TOKYO, Jan 5 (Reuters) - Japan's foreign minister said on Monday Tokyo had protested over Chinese gas drilling in a disputed East China Sea field, which it called regrettable, and urged Beijing to resume talks quickly.

Foreign Minister Hirofumi Nakasone said China had been drilling in violation of a June 2008 agreement with Japan and that Tokyo had protested as soon as it became aware. He did not specify when this happened.

In a deal touted as a breakthrough after years of recriminations, China and Japan agreed last June to jointly develop gas fields and share profits in disputed areas of the East China Sea.

"Under last June's agreement, we were meant to continue negotiations about the areas on which there was no political consensus. So this is most regrettable and we are protesting to the Chinese government," Nakasone told reporters.

"I believe holding talks quickly is the most important thing at this point," he said.

The Chinese foreign ministry said in a statement on its website at the weekend that developing the field was an "inherent sovereign right of China".

Nakasone said that statement was unacceptable to Japan.

Estimated net known reserves in the disputed fields are a modest 92 million barrels of oil equivalent, but both countries have pursued the issue because there may be larger hidden reserves.

A Japanese newspaper report said at the weekend that the Chinese drilling had been discovered at the Tianwaitian field.

Chinese operator CNOOC LTD said in April 2007 it had begun producing gas at the Tianwaitian field despite objections from Japan.

The field's output in 2007 was equivalent to a relatively modest 4 million cubic feet per day, according to state-controlled CNOOC.

But an industry source said in June the actual output was running at 500,000 cubic metres a day (17.76 million cubic feet). (Reporting by Isabel Reynolds; Editing by Paul Tait)