The Democratic People's Republic of Korea (DPRK) foreign ministry on Sunday denied a letter was sent to US President Donald Trump, state news agency KCNA reported.
"We cannot know whether the US President is referring to exchanged letters in the past, but our top leadership has never sent any letter to the US President," said a statement.
The US President said in last August that he had received a three-page "very beautiful letter" from Kim Jong Un and added he could have another meeting with him.
Speaking at a daily press briefing on Saturday, Trump said he had recently received another letter from Kim without providing any details.
In response to the question if he was worried that the DPRK would take advantage of US's current focus on fighting against the COVID-19 pandemic, Trump insisted: "I think we are doing fine."
"I think right now you would be at war essentially in some form… it would be raging with North Korea (DPRK) if I weren't president," he claimed. "We are doing just fine with North Korea (DPRK), just fine. You will see how it all ends up."
Trump sent a letter to the DPRK leader last month, which the KCNA reported was aimed at propelling the relationship between the two countries and expressing his intent to render cooperation in the anti-epidemic work.
Negotiations between the US and the DPRK have been deadlocked over sanctions relief and what the DPRK would be willing to give up in return since a summit between Kim and Trump broke down in Vietnam over a year ago.
The DPRK has conducted a series of weapon tests and artillery firing drills in recent months. The country is under multiple sanctions from the United Nations, the United States and others over its banned weapons programs.