Seoul: Yoon Suk Yeol, the president of South Korea, declared on Tuesday that the country's alliance with the United States has been upgraded to one that is "nuclear-based" in response to the rising military threat from North Korea.
Yoon was making reference to his April discussions with US Vice President Joe Biden regarding Washington's willingness to provide Seoul with more information about its nuclear preparations in the event of a potential conflict with nuclear-armed North Korea.
In a speech commemorating South Korea's Memorial Day, Yoon stated that North Korea "is improving its nuclear and missile capabilities, and has legislated the use of nuclear weapons."
The two leaders decided to strengthen the so-called US extended deterrence, which calls for the use of US nuclear weapons to defend the South, at their summit in Washington.
According to Yoon, the US-South Korea alliance has been upgraded to a "nuclear-based" alliance.
North Korea attempted to launch its first spy satellite last week, but the rocket and its payload crashed into the ocean. This year, the country tested firing its largest intercontinental ballistic missile.
In a rare and prompt admission of failure, North Korea promised to try again and launch a satellite into orbit to bolster its military surveillance capabilities.
The launch was roundly denounced as a violation of UN Security Council resolutions prohibiting North Korea from using ballistic missile technology. The ban has been rejected by Pyongyang because it infringes on its sovereign right to space exploration and self-defense.
While Yoon characterised his discussions with Biden as a commitment to use US nuclear weapons in the event of a nuclear attack from North Korea, Biden reaffirmed a promise "to make every effort to consult" with allies before using a nuclear weapon.
Yoon did not go into further detail on the subject and spent the majority of his Memorial Day speech paying tribute to those who had given their lives in the service of the nation.
A significant portion of the rocket launched by the North on May 31 is being recovered at sea off the west coast of South Korea by the military of that country.