Former National security adviser John Bolton gestures Monday while speakings at the Center for Strategic and International Studies in Washington. Credit: Pablo Martinez Monsivais | AP

WASHINGTON — Former national security adviser John Bolton gave a characteristically pessimistic outlook on the prospects for getting North Korea to give up its nuclear weapons as he made his first public appearance since he was ousted from his post by President Donald Trump.

Bolton made no mention of Trump in his speech to a forum on Korean security on Monday and avoided any discussion of the president in a brief question-and-answer session that followed. But he made it clear that he does not expect much progress in the stalled talks even though Kim Jong Un has halted nuclear weapons tests and met three times with Trump.

The North Korean leader has made a “strategic decision” to do whatever he can to keep his country’s nuclear weapons, and that is an “unacceptable” threat to the world, the famously hawkish former U.N. ambassador said.

“Under current circumstances, he will never give up nuclear weapons voluntarily,” Bolton said at the forum, hosted by the Center for Strategic and International Studies.

Trump fired Bolton this month amid policy disagreements over North Korea and other issues.

The Republican president has said that Bolton’s views set the United States back “very badly” in talks with the North and added that “maybe a new method would be very good.”

Bolton has insisted the North should follow the Libyan path of denuclearization by fully eliminating its nuclear program upfront in a possible deal with the United States, a view he repeated at the security forum.

Asked during the question-and-answer session if “romance diplomacy” is effective — a reference to the warm letters that Trump has exchanged with Kim — Bolton declined to comment.

He warned that there is a danger not just from North Korea’s own weapons but the potential that it could sell missiles or technology to other states.

The United States, Bolton said, is the only country in the world that can stop nuclear proliferation but it must act before it is too late. He said there should be “serious discussions” about strategies, including military force, to counter North Korea’s weapons program.

“If you believe, and you may not, that it is unacceptable for North Korea to have nuclear weapons at some point military force has to be an option,” he said.

Later, he stressed that time may be running out to resolve the issue.

“Every day that goes by makes North Korea a more dangerous country,” he said. “You don’t like their behavior today? What do you think it will be when they have nuclear weapons that can be delivered to American cities? You want to wait until then to act or do you want to act now?”

North Korea recently praised Trump for saying Washington may pursue an unspecified “new method” in nuclear negotiations with Pyongyang. Those talks have been stalled for months by disagreements over trade-offs between sanctions relief and disarmament steps.