President Donald Trump and North Korea's leader Kim Jong-un stand on North Korean soil while walking to South Korea in the Demilitarized Zone (DMZ) on June 30, 2019, in Panmunjom, Korea.

North Korea's mission to the United Nations has accused the U.S. of being "obsessed with sanctions" and "more and more hell-bent on hostile acts" against Pyongyang.

North Korea's delegation to the UN said Wednesday that the country was responding to a letter sent to all UN member states late last month. In it, the U.S. — alongside the U.K., Germany and France — called on countries around the world to implement tougher sanctions on Pyongyang.

The mission said the letter was sent by the U.S. on June 29, the same day President Donald Trump tweeted he would like to shake hands with leader Kim Jong Un during his visit to the demilitarized zone on the Korean Peninsula.

"What can't be overlooked is the fact that this joint letter game was carried out by the Permanent Mission of the United States to the UN under the instruction of the State Department, on the very same day when President Trump proposed for the summit meeting," a press statement from the North Korea mission said.

The meeting on Sunday, which saw Trump become the first sitting U.S. president to set foot in the isolated regime, culminated in the pair agreeing to resume talks aimed at getting Pyongyang to give up its nuclear weapons program.