The U.S. and several allies on Sunday called for an open emergency meeting at the United Nations Security Council following North Korea's latest nuclear test.

"We along w/Japan, France, the UK and S.Korea have called for an emergency Security Council meeting on N.Korea in the open tomorrow at 10am," U.S. envoy to the global body, Nikki Haley wrote on Twitter.

The announcement came after UN Secretary-General Antonio Guterres joined world leaders in condemning the test as a "serious breach" of international law.

The test "undermines international non-proliferation and disarmament efforts", Guterres said in a statement that described it as "profoundly destabilizing for regional security".

Earlier in the day, U.S. President Donald Trump would not rule out an attack in retaliation. Treasury Secretary Steve Mnuchin told Fox News Washington is prepping new round of economic sanctions that would end “all trade and other business" with the North.

North Korea on Sunday claimed to have detonated a new hydrogen bomb, confirming suspicions of the reclusive state's sixth-ever nuclear test after outside monitors noted a magnitude-6.0 earthquake -- five or six times stronger than one created by a nuclear test last year by the autocratic island nation.

Pyongyang's official KCNA news agency announced Sunday the "perfect" test involved a hydrogen bomb that could be mounted on an intercontinental ballistic missile, or ICBM.

"The H-bomb test was carried out to examine and confirm the accuracy and credibility of the power control technology, and internal structural design newly introduced into manufacturing the H-bomb to be placed as the payload of the ICBM," according to KCNA.

The agency published images earlier Sunday that showed images of leader Kim Jong-un inspecting a new H-bomb warhead.