China's requests for consultations under WTO rules and its objection to tariffs were based on an erroneous conclusion that the steel and aluminum tariffs were "global safeguard" measures to protect industry against a surge of imports, the communication issued by the U.S. Trade Representative's (USTR) office said.

But USTR said that the steel and aluminum tariffs were put in place on national security grounds. WTO rules include an exemption for measures related to national security.

USTR said it would not engage in discussions with China about its safeguard objections to the tariffs.

(Reporting by David Lawder; Editing by Susan Thomas)