U.S. prepared to use force on North Korea 'if we must': U.N. envoy

North Korean leader Kim Jong Un looks on during the test-launch of the intercontinental ballistic missile Hwasong-14 (Photo: Reuters)

The United States cautioned on Wednesday it was ready to use force if need be to stop North Korea's nuclear missile program but said it preferred global diplomatic action against Pyongyang for defying world powers by test launching a ballistic missile that could hit Alaska.

U.S. Ambassador to the United Nations Nikki Haley told a meeting of the U.N. Security Council that North Korea's actions were "quickly closing off the possibility of a diplomatic solution" and the United States was prepared to defend itself and its allies.