Defense Secretary James Mattis has on many occasions advocated diplomacy with North Korea, but on Aug. 9 he changed his tone and issued Pyongyang a stern warning, cautioning the country that if it doesn't work with the U.S., it could be in trouble.
"The DPRK must choose to stop isolating itself and stand down its pursuit of nuclear weapons," read a statement from Mattis, reports CBS News. "The DPRK should cease any consideration of actions that would lead to the end of its regime and the destruction of its people."
Mattis' remarks come amid reports that North Korea was able to miniaturize a nuclear warhead and fit it on a missile, while the Asian nation said on Aug. 9 that its government was looking into the possibility of attacking Guam, according to The Associated Press.
"While our State Department is making every effort to resolve this global threat through diplomatic means, it must be noted that the combined allied militaries now possess the most precise, rehearsed, and robust defensive and offensive capabilities on Earth," Mattis said in the statement, notes CNN. "The United States and our allies have the demonstrated capabilities and unquestionable commitment to defend ourselves from attack."
He also urged North Korean leader Kim Jong Un to "take heed of the United Nations Security Council's unified voice, and statements from governments the world over, who agree the DPRK poses a threat to global security and stability."
Mattis' approach to North Korea is part of a measured "pressure campaign" that the U.S. and its allies have mounted against Pyongyang, State Department spokesperson Heather Nauert said.
"The United States is on the same page, whether it's the White House, the State Department, we're speaking with one voice," Nauert explained, adding that the campaign "is working" and "is ratcheting up the pressure every day."
Tensions have been rising between the U.S. and North Korea after new sanctions were leveled against the reclusive country by the U.N., notes AP.
"We will make the U.S. pay by a thousand-fold for all the heinous crimes it commits against the state and people of this country," North Korea said after the sanctions were announced.
The sanctions came after Pyongyang tested intercontinental ballistic missiles, one of which was said to be able to to reach the U.S. mainland. Experts estimate North Korea has up to 60 nuclear weapons.
"North Korea had best not make any more threats to the United States," President Donald Trump said. "They will be met with fire and fury like the world has never seen."