BEIJING (AP) — China's government says it has asked for a temporary hold on a U.S. request for United Nations sanctions against ships accused of violating trade restrictions on North Korea while it studies what entities are involved.

A foreign ministry spokesman, Geng Shuang, said Tuesday that the request to ban violators from global ports covers a "large number of ships and entities" and Beijing needs time to investigate.

The United States requested the sanctions following reports foreign traders are helping North Korea violate limits on oil imports and other trade imposed in an effort to pressure Pyongyang to stop nuclear and missile development.

China was long North Korea's diplomatic protector but has supported the latest rounds of sanctions out of frustration with Pyongyang's weapons development.