Trump: 'Fire and fury' warning to North Korea maybe not enough

U.S. President Donald Trump has hardened his warning that North Korea would face "fire and fury" if it kept threatening the U.S., saying maybe that tough talk "wasn't tough enough."

But U.S. Defense Secretary Jim Mattis appeared to step back from his boss' dire rhetoric, describing the prospect of war as "catastrophic" and adding that diplomatic efforts to solve the North Korea nuclear crisis were yielding results.

Trump in his new remarks on Aug. 10 also warned North Korea it should be "very, very nervous" of the consequences if it even thinks of attacking U.S. soil, after nuclear-armed Pyongyang said it was readying plans to launch missiles towards the Pacific territory of Guam.

The Republican billionaire dismissed any criticism of his "fire and fury" warning of Aug. 8, citing threats made by the regime of Kim Jong-Un to both Washington and its allies.

"It's about time that somebody stuck up for the people of this country and for the people of other countries. So if anything, maybe that statement wasn't tough enough," Trump said.

Trump also said China, Pyongyang's main diplomatic ally, could "do a lot more" to pressure Kim to end his country's nuclear weapons and ballistic missile programs.

Trump's comments, made from his golf club retreat in New Jersey, came after the North announced a detailed plan to send four missiles over Japan and towards Guam, where some 6,000 U.S. soldiers are based.

Pyongyang said the scheme to target the island, a key U.S. military outpost in the western Pacific, was intended to "signal a crucial warning" as "only absolute force" would have an effect on a U.S. leader "bereft of reason."

Trump fired back with gusto.

"If North Korea does anything in terms of...