SEOUL, Sept. 28 (UPI) -- When North Korea announced its fifth nuclear test on Sept. 9, the missive was delivered from Pyongyang's Nuclear Weapons Institute.
The organization's name, however, was not included in the announcement North Korea made after its fourth test, in January, South Korean newspaper JoongAng Ilbo reported Wednesday.
The Nuclear Weapons Institute was first mentioned on North Korea state media on March 9, when Pyongyang stated Kim Jong Un met with nuclear scientists and engineers and provided the group with field guidance.
On Tuesday, North Korea's embassy in Russia provided an explanation through a press release distributed directly to local media, Russia's RIA Novosti reported.
"Up until recently North Korea has delivered announcements of important events in the name of the government or KCNA, but this time the [fifth] nuclear test was brought to light by the Nuclear Weapons Institute," the North Korean press release read. "The reason we officially disclosed the name of the Nuclear Weapons Institute, a secret agency, was to express confidence regarding the basic completion of nuclear weapons development."
Citing statements from the institute, the North Korean press release also said the structure, operational characteristics, performance and power of the tested nuclear warhead had been checked and confirmed.
"We will continue to take measures for the qualitative and quantitative growth of national nuclear power," North Korea said in its statement, according to Russia press.
Pyongyang has previously stated the test of the nuclear warhead "marks the peak" of its nuclear power.