BEIJING (REUTERS) - China's foreign ministry said on Monday (Sept 4) it had lodged "solemn representations" with the North Korean embassy in Beijing over the North's sixth and most powerful nuclear test.

North Korea is clear about China's opposition to its nuclear tests, ministry spokesman Geng Shuang told a regular briefing, adding that China upholds talks as the means to resolve the Korean peninsula issue.

The North said it tested an advanced hydrogen bomb for a long-range missile on Sunday, prompting a vow of "massive" military response from the United States if either it or its allies were threatened.