The Obama administration is expected to replace Glyn Davies, its top point man on North Korea, in the second half of this year, multiple diplomatic sources said Thursday, as Washington's push for the denuclearization of North Korea shows no signs of moving forward.

Chances seem high that Davies, a career diplomat, will be named ambassador to Thailand, according to the sources.

He was appointed to the post of special representative for North Korea policy in January 2012 to succeed Stephen Bosworth.

A month later, he negotiated the Feb. 29 deal with North Korea in which the communist nation agreed to stop nuclear tests, uranium enrichment and long-range missile launches.

But the deal broke as Pyongyang fired a long-range rocket that April.

It remains uncertain whether the U.S. will maintain the post of special representative for North Korea policy at the State Department.

Some sources raise the possibility that the deputy assistant secretary of state for East Asian and Pacific affairs will double as Washington's chief interlocutor with Pyongyang.

James Zumwalt, current deputy assistant secretary, may be tapped as ambassador to a foreign country later this year.

Sung Kim, the outgoing ambassador to South Korea, will likely take the baton from Zumwalt, a source said.

Kim, a Korean-American diplomat, is known for his expertise in the North Korean nuclear issue. (Yonhap)