A spokesperson at the Institute for American Studies, an agency under the North Korea Ministry of Foreign Affairs, said the reports were a "preposterous fabrication" by the United States.
A pro-North Korean newspaper in Japan, in a possible diplomatic signal, said on Thursday that the USA should create the right conditions if it wants talks with Pyongyang.
Seoul officials said it may be "difficult to step forward immediately" to hold talks between Washington and Pyongyang, Yonhap reported.
But Pyongyang is widely suspected of having an arsenal of chemical agents at its disposal, and was accused of using the toxic nerve agent VX to assassinate North Korean leader Kim Jong-un's half-brother, Kim Jong-nam, at an airport in Malaysia a year ago.
"If talks are possible only under the right conditions just as Trump said, the USA should create those conditions", Choson Sinbo said in its article. The paper, also known as The People's Korea, is read by some members of Japan's ethnic Korean community.
"The Trump administration should keep in mind that unless it makes the decision to give up its reckless hostile policy, it won't be given a dialogue opportunity", the newspaper said.
When Europeans watch the news, do they see messages on the screen such as "Threat from North Korea"?
The report likely triggers flashbacks in Washington to the notorious, the nuclear-weapons black market that helped rouge states from North Korea to Iran to attempt to develop nuclear weapons. Tsang has a record of sanctions evasion activities, according to the US Treasury Department.
North Korea has been under United Nations sanctions since 2006 over its ballistic missile and nuclear programs.
The advisory has also alerted the industries of North Korea's deceptive shipping practices.
Despite the denials, North Korea remains one of the only countries not signed to the Chemical Weapons Convention which outlaws the production, stockpiling, and use of chemical weapons.