NEW YORK/SEOUL -- U.S. President Donald Trump and Vice President Mike Pence have toughened their stance toward North Korea, casting further doubt on next month's historic meeting between Trump and North Korean leader Kim Jong Un.
"It would be a great mistake for Kim Jong Un to think he could play Donald Trump," Pence told Fox News in an interview that aired on Monday evening. Asked if Trump could walk away from the summit, Pence replied, "There's no question."
Pence's remarks came after Pyongyang threatened to call off the meeting with Trump, scheduled for June 12 in Singapore.
"This will only end like the Libya model ... if Kim Jong Un does not make a deal," Pence said, referring to the fate of Libyan leader Moammar Gadhafi, who agreed to denuclearization and was ultimately killed by a militia. "The U.S. is not going to tolerate the regime in North Korea possessing nuclear weapons and ballistic missiles that threaten us and our allies," Pence added, stressing the military option has never been taken off the table.
On Monday morning, before the broadcast of Pence's interview, Trump tweeted, "I want this [summit] to happen, and North Korea to be VERY successful, but only after signing!"
The statements represent a shift in tone from Trump's initial optimistic response to the North's threats to cancel the Singapore summit. "We'll see," the president said last week when asked if the meeting would go ahead.
Trump is reportedly increasingly worried about the embarrassment a failed summit could bring.
On Monday, the president also expressed worries that China was easing pressure on North Korea ahead of the summit. "China must continue to be strong & tight on the Border of North Korea until a deal is made," he wrote on Twitter. "The word is that recently the Border has become much more porous and more has been filtering in."
This follows the president's comments last week that Chinese President Xi Jinping may be influencing the North Korean leader and that Kim's attitude had changed significantly after visiting China for a second time on May 7 and 8.
The statements come ahead of a meeting between Trump and South Korean President Moon Jae-in on Tuesday. Moon arrived in Washington on Monday to attend what would be his third summit with the American president. Moon's mission would be to mediate between the leaders and save the summit from cancellation.
Moon and Trump are set to discuss the interpretation of the term "complete denuclearization," as well as detailed plans regarding peace on the peninsula, according to a statement from the Blue House, South Korea's presidential office.
The two leaders are also expected to exchange views on how the Kim regime should be rewarded if it takes steps toward denuclearization.
"We expect that the meeting between the South Korean and U.S. leaders will play a bridge role, building on the success of the inter-Korean summit in the run-up to the meeting between North Korea and the U.S.," said Nam Kwan-pyo, a director at the Blue House's National Security Council.
North Korea has blasted Washington for trying to force it to unilaterally abandon its nuclear program. Pyongyang also canceled a ministerial meeting with South Korea last week over plans to use B-52 strategic bombers in U.S.-South Korea military drills.
Experts say that Moon and Trump need to agree on an exact definition of complete denuclearization, and what security guarantees can be provided to the Kim regime.
"This summit is very important because it is a good chance to set out the positions of South Korea and the U.S. on denuclearization," said Park Won-gon, an international relations professor at Handong Global University in Pohang. "Moon and Trump should figure out what 'complete denuclearization' means, and what they can offer Pyongyang."
Robert Kelly, professor of political science at Pusan National University in Busan, suggested that delaying the Trump-Kim summit might benefit all parties.
"At this point, the best thing to do would be to postpone the summit until greater common ground among the three players can be found, and let experts on the issues hammer out some consensus," said Kelly.
"But Moon likely opposes that because any delay could open political space for [U.S. National Security Adviser John] Bolton," he added.
"Trump likely wants this summit for the TV attention and a political 'win' he can market at home," in an effort to deflect attention from ongoing scandals, argued Kelly.