Washington (CNN) Continued negotiations between the United States and North Korea hinge on Washington's willingness to make a "bold move" and agree to a peace treaty with Pyongyang, according to an official with close knowledge of North Korea's position on the matter.

If the US is unwilling to replace the armistice agreement that ended the Korean War with a permanent peace that would ensure the survival of North Korean leader Kim Jong Un's regime, Pyongyang will likely not proceed further with denuclearization talks, the source said.

The establishment of a legally binding peace treaty would require the approval of two-thirds of the US Senate.

North Korea is putting pressure on the administration of US President Donald Trump to begin lifting sanctions, according to the official, believing they have done "so much" by freezing nuclear and missile testing, destroying one of their nuclear sites, and facilitating the upcoming repatriation of US service members' war remains.

For his part however, Trump has privately expressed frustration over the perceived lack of progress in the talks, according to a US official, though he regarded the testing freeze as a positive sign. Trump pushed back against that suggestion Monday, tweeting that he is "very happy" with the progress with North Korea, noting a lack of rocket launches and nuclear tests in recent months.