"At some point, people have to recognize that North Korea wants nuclear weapons not just for self-defense, but they still want to reunify the Korean Peninsula under their control," Bolton said.
The former US Ambassador to the UN Bolton made the statements during a speech at a security forum in Washington on Wednesday.
"The long-term security for South Korea will be undermined severely if North Korea gets that deliverable nuclear weapons capability," Bolton told the forum.
Bolton is known for his hardline stance against North Korea and has criticized the country on social media many times in the past several weeks.
It’s important to stand behind our South Korean allies, but if we pay heed to the lessons of history, talking to #NorthKorea would be fruitless.— John Bolton (@AmbJohnBolton) February 13, 2018
He even accused the US media helping spread Pyongyang's propaganda.
Earlier this week it was revealed that US Vice President Mike Pence was set to hold a would-be historic meeting with North Korean officials during the Winter Olympics in South Korea, but Kim Jong-un's government canceled at the last minute.
John Bolton served as United States Ambassador to the United Nations from 2005 to 2006.