The White House expressed doubts Wednesday about North Korea's claims of a successful hydrogen bomb test, saying the "initial analysis is not consistent" with Pyongyang's claims.

"The initial analysis that's been conducted of the events that were reported overnight is not consistent with North Korean claims of a successful hydrogen bomb test," White House press secretary Josh Earnest said at a press briefing.

Earnest said there is "nothing that's occurred in the last 24 hours" that has caused the U.S. government to change its assessment of the North's technical and military capabilities. Last month when the North claimed the development of an H-bomb, the White House said its information "calls into serious question those claims."

"You've probably seen by now the extensive independent analysis that's been done in the United States and in other countries that includes significant and understandable skepticism of the claims of the North Korean regime," Earnest said Wednesday.

Still, Earnest said that the North's test is "provocative and a flagrant violation of" U.N. resolutions.

He also reiterated the "rock-solid" U.S. commitment to the security of allies South Korea and Japan.

"What we want the North Koreans to do ... is we want the North Koreans to end their provocative acts both in the form of missile tests and nuclear tests, to commit to de-nuclearization and to demonstrate a commitment to pursuing peace and stability on the Korean Peninsula," Earnest said.

"We're not asking them to do that out of charity, we actually also believe that that would be in the interests of the North Korean people and certainly the broader region. And that was the goal of the six-party talks," he said.

Earnest also said U.S. President Barack Obama plans to speak by phone with President Park Geun-hye and Japanese Prime Minister Shinzo Abe.

"Obviously, consulting with our allies in the region and reiterating our steadfast commitment to their security is a priority at this time, and it's something that the president will do personally in his conversations with those two leaders," he said.

National Security Advisor Susan Rice met with Chinese Ambassador Cui Tiankai to discuss the issue, and Deputy Secretary of State Tony Blinken will also be traveling to the region next week to discuss the situation with partners in the region, the spokesman said.

"I think all of it underscores what I was describing earlier, though, which is that the international community is united in our belief that the North Koreans need to end their provocative actions and commit to de-nuclearizing the Korean Peninsula," he said.

U.S. nuclear experts also doubted North Korea's claims, saying its yield is too low to believe that such an advanced bomb, way more powerful than conventional nuclear weapons, has been detonated.

"It is likely that this was not a test of what in the popular literature is interpreted as an H-Bomb, namely a two -stage fission-fusion weapon developed by the major nuclear-weapon states capable of obtaining explosive yields of hundreds or thousands of kilotons," said David Albright, a nuclear expert heading the Institute for Science and International Security in Washington.

South Korea's spy agency believes that the yield of Wednesday's test is 6 kilotons and a 4.8-magnitude temblor was detected. In comparison, the yield of the nuclear device North Korea tested in

2013 was 7.9 kilotons and it caused a 4.9-magnitude earthquake.

"If North Korea had indeed tested this type of H-bomb, the device's yield would be expected to be many tens of kilotons, at least," Albright said. (Yonhap)