TOKYO -- Japan's defense minister, Satoshi Morimoto, said on Friday that he wanted to revise his nation's security alliance with the United States to place more emphasis on the threat from China to islands at the center of a territorial dispute.
Mr. Morimoto said he wanted to update a set of guidelines that govern how the two allies' militaries would cooperate during a crisis to include the potential for a maritime clash with China. Tensions between Japan and China have risen in recent months over the contested islands in the East China Sea known as the Senkaku in Japan and Diaoyu in China.
In a sign of the emotions conjured by the territorial dispute, China has kept up the pressure on Japan by sending paramilitary ships into waters around the islands, which are Japanese controlled but also claimed by China and Taiwan. On Friday, Japan's Coast Guard said Chinese maritime surveillance ships had sailed into Japanese-claimed waters near the islands for the 21st consecutive day.
Mr. Morimoto did not specify exactly what changes he would seek in the agreement. He told reporters that he had already informed the United States of Japan's desire to revisit the guidelines, and on Friday sent the vice minister of defense, Akihisa Nagashima, to Washington for talks.
Mr. Morimoto noted that the last time the United States and Japan changed the guidelines was in 1997, in response to tensions with North Korea over its nuclear program.
"The situation in Asia is not limited to the Korean Peninsula, but there is also the problem of China's increasing maritime activities," Mr. Morimoto said. "In light of the qualitative changes in the security environment, I want to start a revision of the present state of the U.S.-Japan alliance."
Two years ago, Secretary of State Hillary Rodham Clinton said that the islands fell under the security alliance, requiring the American military to come to Japan's aid during a possible clash there. The United States currently bases around 50,000 military personnel in Japan, with more than half of them on Okinawa, near the disputed islands.
However, some in Japan have questioned whether the United States would actually risk a war with China over what are essentially barren rocks surrounded by shark-infested waters. Japanese leaders have said that they want Washington to go a step further and openly support their claims to the islands.
While the United States has maintained its neutrality, Chinese officials have said that Washington bears some responsibility in creating the current dispute. They say the United States essentially took sides in 1972, when it returned the islands along with Okinawa to Japan without consulting China.
Friday's effort to reach out to Washington is also in line with the conservative stance of Japan's current prime minister, Yoshihiko Noda, who has sought to tighten ties with the United States. Relations were damaged three years ago when one of Mr. Noda's predecessors, the left-leaning Yukio Hatoyama, tried to scrap a laboriously negotiated agreement to relocate a United States Marine air base.
The vice minister, Mr. Nagashima, will also try to smooth out tensions with the United States over a Japanese decision to cancel a joint military drill that was to have taken place this week. The drill, which would have simulated the recapture of a remote Japanese island from an unspecified foreign invader, was apparently deemed by Japan to be too provocative to China. However, some American officials have privately expressed displeasure at the cancellation, saying it sent the wrong signal to China that Japan was willing to compromise on security.
This article originally appeared in The New York Times.