US ambassador to the United Nations, Nikki Haley, has said Washington is prepared to use military force to defend itself after North Korea successfully launched an intercontinental ballistic missile on Tuesday (4 July)."One of our capabilities lies with our considerable military forces. We will use them if we must, but we prefer not to have to go in that direction," Haley told a UN Security Council meeting on Wednesday. She called on the international community to stay unified and cut off the major sources of hard currency flow to North Korea, and also restrict the flow of oil for the regime's military and weapons programs.