SEOUL/WASHINGTON: North Korea showed trademark defiance today, over new UN sanctions imposed after its sixth and largest nuclear test, vowing to redouble efforts to fight off what it said was the threat of a US invasion.

US President Donald Trump said Monday’s sanctions, unanimously agreed on Monday by the 15 member UN Security Council, were just a small step towards what is ultimately needed to rein in Pyongyang over its nuclear and missile programs.

The North’s Foreign Ministry said the resolutions were an infringement on its legitimate right to self-defense and aimed at “completely suffocating its state and people through full-scale economic blockade”.

“The DPRK will redouble the efforts to increase its strength to safeguard the country’s sovereignty and right to existence and to preserve peace and security of the region by establishing the practical equilibrium with the US,” it said in a statement carried by the official KCNA news agency.

DPRK stands for the Democratic People’s Republic of Korea, North Korea’s official name.

The statement echoed comments on Tuesday by the North’s ambassador to the United Nations in Geneva, Han Tae Song, who said Pyongyang was “ready to use a form of ultimate means”.

“The forthcoming measures will make the US suffer the greatest pain it ever experienced in its history,” Han said.

The North’s Rodong Sinmun newspaper also accused South Korea of being Washington’s “puppet”, criticizing Seoul’s agreement with the United States to amend an existing bilateral guideline that will now allow the South to use unlimited warhead payloads on its missiles.

The UN Security Council agreed to boost sanctions on North Korea, banning its textile exports and capping fuel supplies, and making it illegal for foreign firms to form commercial joint ventures with North Korean entities.

The UN resolution was triggered by North Korea’s test of what it said was a hydrogen bomb.