A top U.S. diplomat on East Asian affairs says the U.S. is bound by a treaty to defend a group of Japanese-administered islands at the center of a territorial dispute with China.

U.S. Assistant Secretary of State for East Asian and Pacific Affairs Kurt Campbell said Thursday that the East Sea islands, known as Diaoyu in Chinese and Senkaku in Japanese, clearly fall under the 1960 U.S.-Japan security treaty, under which Washington will defend Japan if attacked.

Campbell told a hearing of the Senate Foreign Relations Committee’s East Asian and Pacific Affairs subcommittee that he believes the issue should be resolved in a peaceful manner through dialogue.

The U.S. government has reportedly never waivered from its committment to the treaty with Japan regarding the disputed islands, but it has refrained from commenting specifically on the issue since the standoff between Tokyo and Beijing escalated.