US Secretary of State John Kerry has described North Korea's government as "an illegal and illegitimate regime".
Mr Kerry used the unusually tough language as he met Kuwait foreign minister Sabah Al Khalid Al Sabah on Friday and credited the Gulf nation for its efforts in countering the North's proliferation activities.
Kuwait has "recently taken steps to curb flights and to make sure that revenues from workers are not sustaining an illegal and illegitimate regime in North Korea", Mr Kerry said.
The US routinely condemns North Korea's nuclear and missile tests as violations of UN Security Council resolutions and is also deeply critical of the North's human-rights record.
It is less typical for US officials to question directly the legitimacy of the hereditary regime of leader Kim Jong Un.
"We do not and will not accept North Korea as a nuclear-armed state," says @JohnKerry following 2+2 meeting with #ROK ministers.
— Steve Herman (@W7VOA) October 19, 2016