North Korea's state-run media insisted Thursday that officially ending the 1950-53 Korean War is the "first process" if the peninsula is going to achieve peace.

The North's Rodong Sinmun newspaper described the need for a formal peace treaty as "the demand of our time" while also lamenting the "abnormal" lack of trust between Washington and Pyongyang.

The United States has repeatedly made clear its view that the Korean War should only be closed once North Korea denuclearizes, although the latter sees an official state of peace as a security guarantee from Washington.

To further complicate the standoff, South Korea already agreed with the North that they will seek to end the war by the end of this year following decades of tensions since an armistice was signed by American, North Korean and Chinese officials in 1953.

Seoul's presidential office added further pressure Monday when spokesman Kim Eui-kyeom told reporters that South Korea is asking the North to "speed up its denuclearization process" and the U.S. to "show sincere efforts about corresponding measures that North Korea is demanding".

Pyongyang has accused Washington of being too focused on sanctions and making "gangster-like demands" since the unprecedented summit between Chairman Kim Jong-un and President Donald Trump on June 12.