The United Nations Security Council will hold an emergency meeting Monday after Pyongyang claimed to have successfully tested a hydrogen bomb that could be loaded on to a long-range missile.
The council will meet in New York this afternoon to discuss a course of action in response to the apparent escalation of North Korea's nuclear arms programme.
South Korea has said it has carried out a live fire ballistic missile test in response to North Korea's threats.
The US said any threat to it or to its allies would be met with a "massive military response".
The United States' most senior military officials yesterday briefed President Donald Trump on the military options available to him.
His Defence Secretary James Mattis said that while the US did not want to see the "total annihilation" of North Korea, he warned that they had many options to do so if North Korea threatened the US, its territories or its allies.
In addition the US said it may stop trading with any country that does business with North Korea.
Both China and Russia have also expressed deep concern at Pyongyang's tests.
The EU has also indicated it is prepared to adopt further sanctions against North Korea.