The White House says it can't confirm a North Korean nuclear test, but said the U.S. would condemn any violations of United Nations Security Council resolutions.

North Korea said it has conducted a hydrogen bomb test — a move that would put the country a step closer to improving its still-limited nuclear arsenal.

National Security Council spokesman Ned Price said late Tuesday that the U.S. is monitoring the situation "in close coordination with our regional partners."

"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," he said,

Price said the U.S. is "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."

North Korea conducted its first nuclear test in 2006 and, until today has done so twice since, Price said, "but we have consistently made clear that we will not accept it as a nuclear state."

"We will continue to protect and defend our allies in the region, including the Republic of Korea," he said, "and will respond appropriately to any and all North Korean provocations."