U.S. Defense Secretary Leon Panetta says he is concerned that territorial disputes in the Asia-Pacific region may result in a conflict that could spread.

Panetta spoke to reporters before arriving Sunday in Tokyo, where he began a week-long visit to the region.

Anti-Japan protests swept across China on Sunday in the latest showing of public anger with Japan over disputed islands in the East China Sea.

Both countries claim the resource-rich island chain region.

Panetta urged the countries to avoid provocative behavior.

“I am concerned that when these countries engage in provocations of one kind or another over these various islands that it raises the possibility that a misjudgment on one side or the other could result in violence and could result in conflict, and that conflict would then have the potential of expanding,” he warned.

Panetta said he will urge China to engage in dialogue with nations of the Association of Southeast Asian Nations, or ASEAN. The goal will be to create a format for resolving such disputes, he said.

Some of the anti-Japan protests in China have turned violent.

The Japanese Embassy says protesters have set fire to Japanese factories, sabotaged assembly lines, looted stores and broken into Japanese businesses.

Japanese Prime Minister Yoshihiko Noda on Sunday deplored the violence and urged both sides to share information and maintain close contacts.