North Korea: US diplomacy is gaining results, says Mattis

North Koreans protest the UN's sanctions against the country

North Koreans protest the UN's sanctions against the country

Mattis made the remarks to reporters at an event in California on Thursday, adding that the US prefers a diplomatic approach to the North Korean threat. "It does not need another characterization beyond the fact that it would be catastrophic".

Maloney noted that Defense Secretary James Mattis has said that diplomatic efforts to contain the North Korea are working, and should remain the favored means of resolving the crisis.

Speaking to journalists at his New Jersey golf club, the President said that he didn't think his comments had been "tough enough".

Meanwhile, various media outlets have reported that North Korea now has the ability to miniaturize a nuclear warhead for placement on an intercontinental ballistic missile and the regime has threatened to "envelope Guam with fire".

The Pentagon chief on Wednesday issued a carefully worded statement telling North Korea it would be "grossly" outmatched in any conflict with the U.S., and warning Pyongyang to stop considering any action that risked "the destruction of its people".

The South Korean government has maintained that it is open to dialogue with the North, and that a diplomatic solution to the DPRK issue could be achieved.

Mattis referred to that two-track policy on Wednesday.

Secretary of State Rex Tillerson told reporters on Wednesday that Americans had "nothing to fear" from Trump's remarks, and that they had instead been an attempt to use language that Kim Jong Un "would understand".

Trump responded to a question about a new report in which US intelligence analysts have "assessed that North Korea has produced a miniaturized nuclear warhead, according to multiple sources familiar with the analysis of North Korea's missile and nuclear program", CNN reported.

"It's [North Korea's] aligning the United Nations in very serious sanctions, and I would just tell you that it did not happen by accident", Mattis said.