North Korea's ruling party newspaper says the country achieved a perfect success in its final test of the Hwasong-17 intercontinental ballistic missile on November 18. It also noted that leader Kim Jong Un had instructed scientists to declare the completion of the ICBM's development by the end of this year.

On Sunday, the Rodong Sinmun reported on a letter sent to Kim by Academy of Defense Science members who were involved in the ICBM's development.

In it, they expressed their gratitude to Kim and called the test launch a perfect success.

The letter also reveals that Kim mentioned the preparation of an underground launch pad, which would make it difficult to detect launches of the Hwasong-17 and intercept it. The ICBM can reportedly reach the entire US mainland.

The newspaper also reported that Kim joined scientists at a photo session along with his daughter.

It quoted Kim as stating that the North's nuclear deterrent would be expanded and bolstered at an exceptionally rapid speed.

Kim reportedly promoted more than 100 people involved in the missile's development, including academy president Jang Chang Ha, who became a general.

The new 22-wheel mobile launching pad for the ICBM-class missile was awarded the title of "DPRK Hero."

The newspaper article apparently intends to emphasize that the nuclear and missile programs are Kim's achievements before Tuesday, when the country marks the fifth year since declaring its nuclear force was completed.