With a shake-up of President Barack Obama's national security team in full swing, major changes are expected in the line-up of key officials handling Korea issues.

Kurt Campbell, assistant secretary of state for East Asian and Pacific affairs, is certain to quit as Secretary of State Hillary Clinton leaves the department this week.

Campbell will likely stay in office for at least a few more weeks until his successor is decided and completes the Senate confirmation process.

Multiple sources say there is a two-way competition to replace Campbell, between Daniel Russel, senior director for Asia at the White House National Security Council, and Michael Schiffer, former deputy assistant secretary of defense for East Asian affairs.

If Russel is tapped to move to the department, Mark Lippert, the assistant secretary of defense for Asia and the Pacific, may fill the White House post, a diplomatic source said.

Campbell's deputy, James Zumwalt, is expected to continue his work for the time being. The career diplomat has served as deputy assistant secretary at the Bureau of East Asian and Pacific affairs for just about a year.

State Department arms control envoy and Iran sanctions czar Robert Einhorn will no longer deal with sanctions on North Korea, focusing solely on the Iranian issue, according to another source.

Dan Fried, a former assistant secretary of state for Europe, will head a new sanctions coordination office at the department for handling a broader policy, added the source.

Meanwhile, the White House announced that Gary Samore, top aide to Obama and coordinator for arms control and weapons of mass destruction, proliferation and terrorism, will retire.

Samore has been appointed executive director of Harvard Kennedy School's Belfer Center for Science and International Affairs. (Yonhap News)