NIIGATA, Japan — Seeking broader international support for opposing China’s claims to airspace over the East China Sea, Japan has asked the United Nations agency that oversees civil aviation to look into whether the newly created Chinese air defense zone could endanger civilian airliners, the Foreign Ministry said Saturday.

The ministry said that it submitted a proposal for the agency, the International Civil Aviation Organization, to examine whether China’s move could threaten the order and safety of international aviation in the area. Though the organization can make only nonbinding recommendations, Japan appears to be hoping that the heightened international scrutiny will force China to back off its declared intent to control the airspace with military measures if necessary.

China’s new “air defense identification zone” covers a broad section of sea that includes islands claimed by both nations, and overlaps with a zone claimed by Japan since the late 1960s. Japan views the zone, which China declared last week, as a new move to gain control of the islands, known as the Senkaku in Japan and Diaoyu in Chinese.

China has said its new zone would not affect civilian air traffic, and was aimed instead at stopping Japanese military aircraft from entering airspace that it says rightfully belongs to China. However, China says that all aircraft, including commercial flights, must submit a flight plan before entering the zone.