US is losing patience with North Korea over its 'dangerous nuclear intentions'
North Korea's leader is "begging for war", the US ambassador has said at an emergency meeting of the UN Security Council.
Ambassador Nikki Haley said the US would look at countries doing business with North Korea and planned to circulate a resolution this week with the goal of getting it approved by September 11.
"Enough is enough. War is never something the United States wants. We don't want it now. But our country's patience is not unlimited," Ms Haley said.
"The United States will look at every country that does business with North Korea as a country, that is giving aid to their reckless and dangerous nuclear intentions."
The move came as US President Donald Trump spoke by phone with South Korean President Moon Jae-in and agreed that Sunday's underground nuclear test by North Korea was a grave provocation that was "unprecedented".
The two leaders also agreed to remove the limit on the payload of South Korean missiles.
Scheduled after North Korea said it detonated the hydrogen bomb, the emergency UN session also came six days after the council strongly condemned what it called Pyongyang's "outrageous" launch of a ballistic missile over Japan.
Less than a month ago, the council imposed its stiffest sanctions yet on the reclusive nation.
But the US resolution faces an uncertain future. Russia and China have both proposed a two-pronged approach: North Korea would suspend its nuclear and missile development, and the US and South Korea would suspend their joint military exercises.
Washington and Seoul say the manoeuvres are defensive, but Pyongyang views them as a rehearsal for invasion. The North recently requested a Security Council meeting about the war games.
The US says there is no comparison between its openly conducted, internationally monitored military drills and North Korea's weapons programmes, which the international community has banned.
Russian Ambassador Vassily Nebenzia told reporters after yesterday's meeting that sanctions alone will not solve the issue and there need to be negotiations too. "Resolutions aimed solely at sanctioning North Korea have not worked well before," Mr Nebenzia said.
Matthew Rycroft, the UK ambassador to the UN, described the situation as "disturbing and unprecedented", but said it was "clear" sanctions applied by the Security Council on North Korea were "having an effect".
He called on the Security Council to condemn the latest test, and said: "We continue to wish for a peaceful way forward: dialogue will always be our end goal but returning to dialogue without a serious sign of intent from Pyongyang would be a set up to failure.
"North Korea must change course to allow a return to dialogue. Were they to do so the opportunity exists to end this crisis.
"Until that moment we must stay the course on sanctions and continue, as the Secretary General has called for, to present a united front."
He restated his calls for a new UN Security Council resolution, and said in light of the latest test: "We must increase the pace of implementation of existing sanctions and work rapidly towards the adoption of a new and effective resolution."