The United States will work with allies and partners to "deeply isolate" North Korea and the communist regime will continue to remain "an outcast" unless it lives up to its denuclearization commitments, the White House chief of staff said Sunday.

Denis McDonough made the remark in an interview with CNN in response to a question on what new steps the U.S. will be taking to punish Pyongyang for its fourth nuclear test last week that the North claimed involved a hydrogen bomb.

"As it relates to what steps we'll continue to take. Well, what we'll continue to do is work not just with South Korea and Japan but also with China and Russia to deeply isolate the North Koreans," McDonough said on CNN's "State of the Union."

"I'm not telling you that I think that this is going to resolve this issue overnight. We're going to have to continue to squeeze the North Koreans until they live up to their prior commitments.... Until they do it, they'll remain where they are which is an outcast unable to provide for their own people."

The official said that the North should get back to a 2005 denuclearization deal in which Pyongyang pledged to abandon all its nuclear weapons and programs in exchange for diplomatic recognition, economic assistance and other concessions.

The U.S. has condemned the North's latest nuclear test but expressed skepticism about Pyongyang's claims that it detonated a thermonuclear device that is much more powerful than conventional nuclear weapons.

On Sunday, the U.S. sent a B-52 nuclear bomber from Guam to fly over South Korea in a show of force designed to send a warning to North Korea and reassure its ally of Washington's security commitment in the wake of the North's nuclear test.

"We obviously did underscore to our South Korean allies last night the deep and enduring alliance that we have with them. Last night was a step towards reassurance in that regard and that was important," McDonough said of the bomber's overflight.

U.S. Deputy Secretary of State Tony Blinken is expected to travel to Tokyo later this week for trilateral vice minister-level talks expected to take place around Jan. 16 with his South Korean and Japanese counterparts to discuss ways to respond to the North's nuclear test, sources said.

Blinken's trip could also include a stop in Seoul, though the itinerary hasn't been finalized yet, they said.

Ahead of Blinken's trip, Washington's chief nuclear envoy, Amb.

Sung Kim, plans to visit Seoul for three-way talks with his South Korean and Japanese counterparts. (Yonhap)