Defense Secretary Austin threatens to 'end' Kim regime if North Korea fires nuclear weapon

Defense Secretary Lloyd Austin on Thursday warned North Korea dictator Kim Jong-un that his deployment of nuclear weapons would lead to the "end" of his regime.

"Any nuclear attack against the United States or its Allies and partners, including the use of non-strategic nuclear weapons, is unacceptable and will result in the end of the Kim regime," Austin said during a press conference at the Pentagon with South Korean Defense Minister Jong-Sup Lee, one day after North Korea fired more than 20 missiles.

South Korea fired into the sea on Wednesday, after a missile from the North landed near its coast. North Korea also let off an intercontinental ballistic missile that officials believe failed in flight, Fox News reported.

"This is a strong warning," Jong-Sup said during the press conference Thursday. 

The United States and South Korea also announced an extension of a joint air force exercise on Thursday in response to the North's missile activities.

North Korea is believed to be close to having fully developed a nuclear warhead that could be affixed, then launched on a ballistic missile.