Enlarge By Lee Jin Man, AP Visitors at the border village of Paju, South Korea, study a sign offering details about North Korea's missiles Tuesday. North Korea test-fired two short-range missiles. WASHINGTON  As North Korea continued to defy the international community by test-firing two missiles Tuesday, the Obama administration faced the same problem that confronted its predecessors: How to convince China to go along with tough U.N. sanctions. While the United States and its allies have sought to punish North Korea over the years as it has pursued a nuclear weapons program, China has continued to prop up the North with food aid, oil and consumer goods. The question is whether that will change in the wake of Monday's North Korean nuclear weapons test. Chinese Foreign Ministry spokesman Ma Zhaoxu reiterated Tuesday that Beijing "resolutely opposed" the test — stronger language than China has used after past incidents. He was silent about what the next step would be. N. KOREA WARNS: S. Korea, U.S. tread lightly NUKE TEST: Defiant move puts U.S., Obama on notice "This strategy of sanctions has not succeeded thus far, and the reason is that China has not implemented sanctions," said Marcus Noland, Asia expert at the Peterson Institute for International Economics . "Ultimately they are more concerned about North Korean instability than North Korean weaponry. They act as an enabler." In a further provocation, North Korea test-fired two short-range missiles off its eastern coast Tuesday. "Our army and people are fully ready for battle … against any reckless U.S. attempt for a pre-emptive attack," the North's state-run KCNA news agency proclaimed. The Obama administration was marshaling international support for new sanctions. "We will take action," State Department spokesman Ian Kelly vowed Tuesday. Kelly said "the door does still remain open" for talks, and "we hope that North Korea will make the right choice and choose to engage constructively." Kelly declined to speculate about what China might do, but many experts say China holds the key. "China is the one country that has the capacity to bring the North Korean regime down," said John Bolton, former U.S. ambassador to the United Nations . "They're afraid to do it because they are afraid the regime itself is so fragile it will collapse," Bolton said. The Chinese government has expressed concern that such an event might send millions of North Korean refugees into China. The United States must balance its desire to press China on North Korea with its economic relationship, including China's huge holdings in U.S. debt, said Larry Niksch, an Asian affairs specialist at the Congressional Research Service. If China fails to cooperate, the United States could resume its previous efforts to prevent banks from doing business with North Korea, and it can pursue the so-called Proliferation Security Initiative, under which it can board ships suspected of importing or exporting nuclear material from the country, said Kongdan Oh of the Brookings Institution. There is some hope that China may finally be reconsidering its support for North Korea, said the Asia Foundation 's Scott Snyder. "The Chinese believed they could make a choice between stability and denuclearization, but I think this test suggests that's a false choice," he said. Guidelines: You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. Read more