North Korea has pledged to redouble the efforts in strengthening its weapons programme and protecting its sovereignty as the country rejected the latest round of economic sanctions imposed by the UN Security Council. The reclusive nation also warned the US would suffer the "greatest pain" for engineering harsh sanctions against Pyongyang.

Late on Monday, 11 September, the top UN body unanimously adopted its ninth package of sanctions on North Korea to punish the hermit kingdom for its recent nuclear detonation. A limited oil embargo and a ban on textile imports were placed as part of the measures although the final resolution was watered down from the initial tougher proposal by the US.

Responding to the UNSC's step, the North said the sanctions were "illegal and evil".

"The 'resolution' was fabricated by the U.S. employing all sorts of despicable and vicious means and methods. The DPRK condemns in the strongest terms and categorically rejects the UNSC 'resolution 2375' on sanctions as a product of heinous provocation aimed at depriving the DPRK [Democratic People's Republic of Korea] of its legitimate right for self-defence and completely suffocating its state and people through the full-scale economic blockade," said North Korea's foreign ministry on Wednesday, 13 September.

This was also the first time the UNSC targeted the country's oil imports while sanctioning the regime.

Before the foreign ministry's comments were released, North Korea's ambassador to the UN Han Tae-song had warned these measures are set to backfire for Washington.

"The forthcoming measures... will make the US suffer the greatest pain it ever experienced in its history," Han said in his first reaction to the sanctions.

The North is "ready to use a form of ultimate means," as the US has "fired up political, economic, and military confrontation," Han added.

North Korea  nuke test celebration
North Korean leader Kim Jong-un reacts during a celebration for nuclear scientists and engineers who contributed to a hydrogen bomb test, in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang KCNA via Reuters