North Korea, in a series of escalating declarations, claimed on Sunday that it has the ability to launch an intercontinental ballistic missile “at any time” and from any location. U.S. Defense Secretary Ash Carter responded by stating that North Korea’s nuclear and ballistic missile capabilities are a “serious threat” and that the U.S. is prepared to shoot down any missile aimed at the United States or any of its allies.

This most recent threat comes days after Kim Jong Un’s New Year’s Eve speech, where he claimed that North Korea is in the “final stages” of developing intercontinental ballistic missiles. President-Elect Donald Trump responded with a tweet saying “It won’t happen!” and a spokesperson for the U.S. State Department commented that it does not believe that North Korea has the necessary capabilities to mount a nuclear warhead onto a ballistic missile. The most recent threat by North Korea was accompanied by a message from the country’ foreign ministry, asserting in a statement that “anyone who wants to deal with [North Korea] would be well advised to secure a new way of thinking after having clear understanding of it.” China and South Korea have denounced North Korea’s threats, warning that a North Korean ICBM test-launch would lead to more severe sanctions and international pressure against the North.