The United States and Japan should act with caution regarding the South China Sea issue, a Foreign Ministry spokeswoman urged on Friday, emphasizing China's resolve to defend its territory.

Spokeswoman Hua Chunying commented after the US and Japan issued a joint statement expressing "serious concerns" on the issue. The two countries released the statement after Japan's foreign and defense ministers met in Washington on Thursday with the US secretaries of state and defense.

Hua said the US and Japan are not parties concerned with the South China Sea issue. "They should have been cautious with their words and actions and respected efforts the regional countries have made to resolve the disputes."