John Bolton, President Trump’s former national security adviser, criticized his old boss over the administration's misguided "rhetorical policy" toward North Korea along with its failure to exert "maximum pressure" during the high-stakes nuclear talks.

Bolton’s comments, which were published late Sunday on Axios, come at a precarious time between Trump and North Korea's leader Kim Jong Un. What once showed glimpses of an unlikely and historic foreign policy victory for Trump, now appears to be teetering on the brink of collapse.

Bolton said he doesn't believe the administration "really means it" when they talk about stopping North Korea's nuclear ambition. He said if they did they would "pursue a different course."

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U.S. officials on Sunday were on high alert due to a possible North Korean missile launch that has been menacingly referred to by Pyongyang as a "Christmas gift." Bolton said in the interview that if Kim makes good on the threat and launches a missile the White House should do something "that would be very unusual" and admit that they were wrong.

Bolton said-- in the event of a missile launch-- he hopes the White House can admit to the failure and then works with allies to "demonstrate we will not accept it." Bolton is seen as a hardliner towards North Korea and has said in the past that as it stands Kim "will never give up the nuclear weapons voluntarily."

Trump fired Bolton in September amid policy disagreements over North Korea and other issues. Trump said at the time that Bolton's view set the United States back "very badly" in talks with the North and added that "maybe a new method would be very good."

The relationship between Trump and Kim has been rocky at best and despite high-profile meetings and positive descriptions from Trump about their relationship, experts have raised concerns about Pyongyang becoming more of a threat.

Anthony Wier, a former State Department official who tracks nuclear disarmament for the Friends Committee on National Legislation, said Pyongyang has “been building new capabilities.”

"As long as that continues, they gain new capabilities to try new missiles to threaten us and our allies in new ways," he said.

Defense Secretary Mark Esper told reporters earlier this week that the U.S. has heard all the talk of a possible upcoming test around Christmas.

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"I've been watching the Korean Peninsula for a quarter-century now. I'm familiar with their tactics, with their bluster," he said. "We need to get serious and sit down and have discussions about a political agreement that denuclearizes the peninsula. That is the best way forward and arguably the only way forward if we're going to do something constructive."

Fox News' Bradford Betz contributed to this report