Bolton said the US has a program in the works that would allow for North Korea's nuclear program to be dismantled within a year.
US Secretary of State Mike Pompeo has been pushing for more follow-up talks to flesh out details of the denuclearization, but no date has been set for when they would take place.
Senator Murphy could not be reached for further comment by Newsweek on Saturday about North Korea's continued nuclear weapons program and what type of response he would like to see from the president.
Bolton told CBS's Face the Nation that Washington has devised a programme to dismantle North Korea's weapons of mass destruction and ballistic missile programs in a year.
"I do not believe it would be possible to verify full dismantlement within a year, nor have I yet seen evidence of a firm DPRK decision to undertake full dismantlement".
The findings support a new, previously undisclosed Defense Intelligence Agency estimate that North Korea is unlikely to denuclearise.
Trump earlier declared that "there is no longer a Nuclear Threat from North Korea", but some officials fear that Kim's latest agreement may be another set of empty promises created to secure concessions from the US while continuing to develop nuclear weapons.
Kim, the U.S. ambassador to the Philippines, met with North Korean Vice Foreign Minister Choe Son Hui for working talks that were believed to be focused on setting the agenda for an upcoming visit to North Korea by Pompeo, according to reports in Yonhap News Agency and MBC television.
TOKYO, Japan - North Korean leader Kim Jong-un has appealed to China's Xi Jinping to help end sanctions against Pyongyang following his landmark summit with US President Donald Trump, a Japanese newspaper reported Sunday, July 1, citing multiple unnamed sources in the two countries.
Evidence collected since the June 12 summit in Singapore points to preparations to deceive the US about the number of nuclear warheads in North Korea's arsenal as well as the existence of undisclosed facilities used to make fissile material for nuclear bombs, according to the report. It also reported Pyongyang has secret production facilities, according to the latest evidence they have.
Bolton said Trump was not being played by Kim and was "very well aware of North Korea's patterns of behaviour over decades of negotiating with the United States".
MP Mark Pritchard, a member of All-Party Parliamentary Group on North Korea, said: 'The Americans will not be taken for fools.
Trump has suspended military exercises in the Korean peninsula after North Korea stopped carrying out missile and nuclear tests.
As U.S. intelligence agencies continue to gather information about North Korea's actions, any breach of the nuclear agreement by Kim could warrant a return to the tense relationship that characterized U.S.