President Donald Trump said his earlier promise of "fire and fury" against North Korea "maybe wasn't tough enough."

Ahn Young-joon / AP

Amid rising international tensions over Pyongyang's nuclear weapons program, President Trump said Thursday that his earlier promise of "fire and fury" against North Korea "maybe wasn't tough enough."

"If North Korea does anything in terms of even thinking about attack of anybody that we love or we represent or our allies or us, they can be very, very nervous," Trump told reporters at his New Jersey golf club where he is on a so-called working vacation. "They should be nervous. Things will happen to them like they never thought possible." Early Friday morning, North Korea issued a new statement in response to Trump's threat from Wednesday, vowing to "mercilessly wipe out the provocateurs making desperate attempts to stifle socialist country." "The US will suffer a shameful defeat and final doom if it persists in extreme military adventure, sanctions, and pressure," it added. The president pushed back on a question of whether the administration is sending the American public mixed messages about the situation with North Korea. Secretary of Defense James Mattis on Wednesday echoed Trump's strong language, saying North Korea needs to "cease any consideration of actions that would lead to the end of its regime and the destruction of its people." However, at a brief news conference Thursday afternoon, Mattis said that "my responsibility is to have military options should they be needed," though diplomacy remains the preferred option. "Right now we're keeping the diplomatic track out in front," he added.

Jonathan Ernst / Reuters / AFP / KCNA Via KNS / STR

When asked about the outcome of a potential nuclear confrontation, Mattis said only that it would be "catastrophic." He also declined to detail US military readiness, saying only that "we are ready" and "I don't tell the enemy in advance what we are going to do." Secretary of State Rex Tillerson provided a calmer message, saying that Americans should "sleep well at night" and "have no concerns" over the threat of attacks from North Korea. Sebastian Gorka, one of Trump's top national security advisers, said earlier this week on BBC that Tillerson isn't in charge of defense strategy, and the idea that he "is going to discuss military matters is simply nonsensical."

A spokesperson for the State Department, Heather Nauert, on Thursday pushed back on Gorka's comments saying that Tillerson should be paid attention.

"I think that everyone has clearly heard what Tillerson's forceful comments have been and continue to be on the issue of DPRK and on other countries as well," Nauert said in a press briefing Thursday. "He's a cabinet secretary. He's the fourth in line to the presidency. He carries a big stick." Gorka later told Fox News that his BBC statements are "fake news 101," adding that he was defining the roles of Secretary of Defense and Secretary of State. "No, I never said that," Gorka said in response to the anchor saying there was audio of his BBC interview. "I said for reporters to force our chief diplomat, the amazing Rex Tillerson to give details of military options is nonsensical. He is the secretary of state. That means you don't understand what the words secretaries of state means. It's fake news. Classic example."



Ahn Young-joon / AP

Despite the confusion, Trump said, "there are no mixed messages" coming from the administration. “It’s about time someone stood up for the people of our country,” he said, adding that his statements were backed up 100% by the military. Trump said that China can do a lot more to help with North Korea, loosely implying that he would ease up on trade actions if China helped the US. "We lose hundreds of billions of dollars a year on trade with China," Trump said. "They know how I feel. It's not going to continue like that. But if China helps us, I feel a lot differently toward trade." He went on to criticize former president Bill Clinton for being "weak and ineffective" with North Korea, and former president Barack Obama for not wanting "to talk about it."

"North Korea better get their act together," Trump said. "They are going to be in trouble like a few nations have been in trouble in this world." He also disagreed with Obama's statement that global warming is the greatest threat, adding that he would like to "de-nuke the world," and see other countries get rid of their nuclear weapons. "Until such time as they do, we will be the most powerful nuclear nation in the world, by far," Trump said.

Earlier on Thursday Senator Marco Rubio called people's criticism of Trump's fiery rhetoric "ridiculous." "They act as if North Korea would act different if he used nicer words," Rubio tweeted. As tensions continued to escalate, the State Department on Thursday issued a travel warning advising US citizens to not travel to North Korea due to the "serious and mounting risk of arrest and long-term detention of US citizens." Meanwhile in Australia, Prime Minister Malcolm Turnbull promised to join the fight if North Korea were to attack the US base at Guam. "The United States has no stronger ally than Australia,” Turnbull told Melbourne radio station 3AW on Friday morning. If North Korea attacked, Turnbull promised that the ANZUS treaty — the military alliance between Australia, New Zealand and the United States — would be invoked for only the second time since its signing in 1951. “We have an ANZUS agreement and if there is an attack on Australia or the United States… each of us will come to the other's aid.” Additional reporting from Brianna Sacks, Mark Di Stefano and Jim Dalrymple II.