In an April summit, President Moon Jae-in and North Korean leader Kim Jong-un agreed to seek such declaration this year through three-way meetings involving the two Koreas and the United States or four-way talks involving the two Koreas, the U.S. and China. Notably, the statement didn't directly criticize Trump.
North Korea warned Thursday that there could be no progress in its denuclearization as it accused some senior USA officials of trying to strengthen worldwide sanctions on Pyongyang.
The foreign ministry said that despite their efforts to work with the US - by stopping their missile launches and nuclear tests - America continues to insist on "denuclearization first", and continues to encourage worldwide sanctions against the North.
"We hoped that these goodwill measures would contribute to breaking down the high barrier of mistrust existing between the DPRK and the USA and to establishing mutual trust".
"However, the U.S. responded to our expectation by inciting worldwide sanctions and pressure against the DPRK", it said in a statement carried by KCNA news agency.
North Korea called out the U.S.' "shameless and impertinent behavior", according to a press release out Thursday via a foreign ministry spokesperson.
North Korea's nuclear weapons program has caused global tension for decades and the rhetoric and threats from Kim and Trump had been especially hostile before their June meeting.
It continued: "Now, the issue in question is that going against the intention of President Trump to advance the DPRK - US relations, some high level officials within the US administration are making baseless allegations against us and making desperate attempts at intensifying the global sanctions and pressure". Pompeo's comments came on the heels of a United Nations report that found North Korea has not stopped its nuclear and missile programs and is violating U.N. sanctions, including through illicit ship-to-ship transfers of oil.
Pyongyang also returned the remains of some United States soldiers killed in the 1950-53 Korean war in a gesture meant to break down mistrust between the countries, it said.
In the meantime, both Koreas are seeking an end of the Korean War. The Korean Peninsula is still technically in a state of war because the fighting ended with a cease-fire, not a peace treaty.
Mr. Kim and Mr. Moon met in April at a highly publicized summit that saw the leaders hold hands and walk together across the border, and then again in a more informal summit in May, just weeks before Mr. Kim met Mr. Trump in Singapore.