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



"We are not looking to the total annihilation of a country, namely North Korea," U.S. Defense Secretary Jim Mattis said after meeting Trump and his national security team.



"But as I said, we have many options to do so."



Trump has previously vowed to stop North Korea developing nuclear weapons and said he would unleash "fire and fury" if it threatened U.S. territory.



Despite the tough talk, the immediate focus of the international response was expected to be on tougher economic sanctions.



Diplomats have said the U.N. Security Council could now consider banning North Korean textile exports and its national airline, stop supplies of oil to the government and military, prevent North Koreans from working abroad and add top officials to a blacklist to subject them to an asset freeze and travel ban.



Asked about Trump's threat to punish countries that trade with North Korea, Chinese Foreign Ministry spokesman Geng Shuang said China has dedicated itself to resolving the North Korean issue via talks, and China's efforts had been recognized.



"What we absolutely cannot accept is that on the one hand (we are) making arduous efforts to peacefully resolve the North Korean nuclear issue, and on the other hand (our) interests are being sanctioned or harmed. This is both not objective and not fair," he told a regular briefing.



On possible new U.N. sanctions, and whether China would support cutting off oil, Geng said it would depend on the outcome of Security Council discussions.



Chinese state-run Xinhua news agency said in an editorial North Korea was "playing a dangerous game of brinkmanship" and it should wake up to the fact that such a tactic "can never bring security it pursues".



While South Korean President Moon Jae-in and Japanese Prime Minister Shinzo Abe agreed on Monday to work with the United States to pursue stronger sanctions, Russia voiced skepticism.



