Defense Secretary Jim Mattis confirmed on Monday that the United States has discussed with South Korea the option of employing tactical nuclear weapons to defend against North Korea’s nuclear weapons program.

“We discussed the option,” Mattis told reporters at the Pentagon, according to the Military Times. “We have open dialogue with our allies on any issue they want to bring up.”

Mattis’s confirmation comes days after North Korea carried out its sixth nuclear test using an intercontinental ballistic missile (ICBM) which is said to be capable of reaching the United States.

Air Force Gen. John Hyten, a STRATCOM commander who met with reporters during Mattis’s visit, told the Military Times that reintroducing the tactical nuclear weapons to the Korean Peninsula could be grave. He said, “I think it is actually a very dangerous term to use, because I think every nuclear weapon that is employed is strategic.”

Without providing further detail, Mattis reportedly said the United States is considering military options against North Korea that would not result in mass casualties for Seoul.

It has been suggested that China could play a role in removing Kim Jong-un from his dictatorial post.

The Military Times noted that tactical nuclear weapons were removed from the South Korean Peninsula in 1991. The move was the result of a prior attempt to get North Korea to abandon its nuclear weapons program, just three years before the historic nuclear deal signed between the DPRK and the United States under the leadership of former President Bill Clinton.

The deal was seen as a failure, and several of the same nuclear negotiators who were commissioned to handle the North Korea nuclear deal were also involved in negotiating the nuclear Iran deal, or Joint Comprehensive Plan of Action (JCPOA).

This month, North Korea has, for the first time, threatened to wage an EMP (electromagnetic pulse) attack against the United States. The threat of such a devastating attack was confirmed by former United States Ambassador to the United Nations John Bolton during an interview with Breitbart News Daily,  during which he suggested considering military action against Pyongyang.

On Tuesday, President Donald Trump delivered his starkest warning yet to the North Korean regime while addressing the United Nations General Assembly.

“The U.S. has great strength and patience, but if it is forced to defend itself or its allies, we will have no choice but to totally destroy North Korea,” Trump warned.

“Rocket Man is on a suicide mission for himself and his regime,” Trump said, referring to Kim Jong-un. “The U.S. is ready, willing, and able, but hopefully, this will not be necessary.”

Trump previously referred to Kim as “Rocket Man” in a tweet Sunday:

Adelle Nazarian is a politics and national security reporter for Breitbart News. Follow her on Facebook and Twitter.