TOKYO -- Japan and China ended talks in disagreement Thursday over their competing claims to gas reserves in the East China Sea and planned to meet again next month, an official said.

Both sides exchanged details about their positions on the dispute and underlined the importance of managing boat traffic in the area to minimize the chance of an unexpected confrontation, Foreign Ministry spokesman Akira Chiba said.

Hu Zhengyue, chief of Chinese Foreign Ministry's Asian Affairs Department speaks at the start of the China and Japan talks in Tokyo, May 18, 2006. China and Japan held a new round of talks on a disputed gas field in the East China Sea in Tokyo on Thursday, but Beijing doesn't expect any breakthrough, the Chinese Foreign Ministry said. [Reuters]

But neither side presented new ideas in the 5 1/2-hour one-day meeting that could break the impasse, he said.

"There was no breakthrough," Chiba said. "There was a deepening of understanding of the viewpoints of each side." .

At the start of the talks, Kenichiro Sasae, head of the Japanese Foreign Ministry's Asia-Oceania Bureau, said the two countries need to cooperate to resolve the issue.

"There are differences in opinions on both sides, but it is important to make progress toward resolving the issue with a broad picture in mind," he said at the start of Thursday's talks.

Hu Zhengyue, chief of the Chinese Foreign Ministry's Department of Asian Affairs, said the two countries should remain optimistic.

"We should be confident about the prospect (of progress). China wants to work hard with Japan so we can make progress," Hu said.

Earlier this week, China warned not to expect any breakthrough at the talks.

The issue has strained relations between Beijing and Tokyo. China claims it has rights to the gas reserves under the sea bed in the East China Sea's Pinghu field, but Tokyo says the two countries should share them.

Repeated meetings between the countries have failed to resolve the dispute.