The US today vowed to respond appropriately to North Korea's provocations after the reclusive nation claimed that it had carried out a hydrogen bomb test.
"We will continue to protect and defend our allies in the region, including the Republic of Korea, and will respond appropriately to any and all North Korean provocations," State Department Spokesman John Kirby said in a statement.
The US at the same time said it cannot confirm the claim of North Korea.
"While we cannot confirm these claims at this time, we condemn any violation of UN Security Council Resolutions and again call on North Korea to abide by its international obligations and commitments," Kirby said.
"We are aware of seismic activity on the Korean Peninsula in the vicinity of a known North Korean nuclear test site and have seen Pyongyang's claims of a nuclear test," he said.
The US is monitoring and continuing to assess the situation in close coordination with its regional partners.
"North Korea conducted its first nuclear test in 2006 and, until today, has done so twice since, but we have consistently made clear that we will not accept it as a nuclear state," Kirby said.