For the first time, Abe referred to a new Chinese project in the East China Sea as “a clear violation” of a 2008 agreement between Japan and China for joint development of gas fields.

Until now, Japan’s official stance was more cautious; it asked Beijing to return to the spirit of the 2008 agreement. Japanese officials were concerned that a more assertive position could provoke China into all but voiding that agreement.

Abe’s harsher comment, made on a TV program on July 5, could potentially turn the gas field development issue into a contentious one similar to the territorial dispute over the Senkaku Islands.

“Since an agreement was reached not to monopolize the resources but to use them for the sake of both nations, I hope China will comply,” Abe said on the TV program.

Japan and China in 2008 agreed to jointly develop the gas field called Shirakaba by Japan and Chunxiao by China. The agreement also called for further discussions on early joint development of other gas fields in the East China Sea near the Japan-China median line.

Shortly before the agreement was reached, the two leaders at the time, Japanese Prime Minister Yasuo Fukuda and Hu Jintao, president of China, confirmed that the East China Sea should be an area of friendship.

Japan recently lodged a protest after it confirmed that China was working on a new project in the area covered by the 2008 agreement.

At a July 3 news conference, Hua Chunying, a spokeswoman for the Chinese Foreign Ministry, said, “There is no change in our stance that joint development should be sought.”

However, she stopped short of referring to China’s new project, an indication that Beijing was taking the position of conducting its own development while acknowledging the existence of the 2008 agreement.

Abe’s more critical comment could be seen as an attempt to prevent Beijing from taking further action that ignores the agreement.

Abe’s Liberal Democratic Party appears set to win a landslide victory in the July 21 Upper House election, which would make it easier for his administration to pursue its policies through the Diet.

But Japan’s relations with China and South Korea remain strained due mainly to sovereignty claims over islands and interpretations of history, particularly events during World War II.

The Japan-China feud over the Senkaku Islands in the East China Sea has led to the suspension of talks on joint development of the gas fields.

China has called on Japan to create an environment for resuming those discussions, underscoring the wide gap between the two nations on the issue.