This file photo taken on August 2, 2017 shows U.S. Secretary of Defense Jim Mattis (C) and U.S. Secretary of State Rex Tillerson (R) arriving for a closed meeting of the Senate Foreign Relations Committee on Capitol Hill in Washington, DC. (AFP PHOTO / Brendan Smialowski)

WASHINGTON, Aug. 9 (Xinhua) -- The Democratic People's Republic of Korea (DPRK) must stand down its pursuit of nuclear weapons, U.S. Secretary of Defense Jim Mattis said in a statement on Wednesday.

"The DPRK must choose to stop isolating itself and stand down its pursuit of nuclear weapons," Mattis said, urging Pyongyang to "cease any consideration of actions that will lead to the end of the regime and destruction of its people."

The U.S. defense chief also warned that the DPRK's actions "will continue to be grossly overmatched by ours and would lose any arms race or conflict it initiates."

On Tuesday, U.S. President Donald Trump issued a warning to the DPRK that appeared to threaten a nuclear war with the Asian country.

"North Korea (DPRK) best not make any more threats to the United States. They will be met with fire and fury like the world has never seen," Trump said at his golf resort in New Jersey.

In response, the DPRK warned of preemptive strikes against the U.S. military base of Guam in the Pacific.

U.S. Secretary of State Rex Tillerson on Wednesday played down the threat from the DPRK, telling Americans to "sleep well at night."

"Nothing that I have seen and nothing that I know of would indicate that the situation has dramatically changed in the last 24 hours," Tillerson told reporters.

"I think Americans should sleep well at night, have no concerns about this particular rhetoric over the last few days," Tillerson added.