WASHINGTON, Feb. 10 -- The United States on Monday expressed "deep disappointment" over Pyongyang's cancellation of a visit for an American envoy to discuss the release of a Korean- American.

Robert King, a special American envoy for human rights issues relating to the Democratic People's Republic of Korea (DPRK), had planned to visit the Asian country on Monday, but Pyongyang rescinded his invitation citing the upcoming war games between the U.S. and the Republic of Korea (ROK) later this month.

"We're deeply disappointed by the DPRK decision for a second time to rescind its invitation for Ambassador King to travel to Pyongyang to discuss Kenneth Bae's release," White House spokesman Jay Carney told reporters at a regular news briefing.

Bae, 45, was detained by Pyongyang in November 2012 and sentenced to 15 years of hard labor for "hostile acts" against the country in late April, 2013. The U.S. State Department said Friday that he was moved from a hospital back to a labor camp on Jan. 20, the same day he made a public appeal for Washington to help get him home.

The DPRK canceled an invitation for King in August last year for a visit focused on securing the release of Bae.

"The DPRK announced publicly in May of 2013 that it would not use the fate of Kenneth Bae as a political bargaining chip," Carney said. "We remind the DPRK that the U.S.-ROK military exercises are transparent, regularly scheduled, and defense- oriented."

He reiterated Washington's call for Pyongyang to grant Bae " special amnesty and immediate release" as a humanitarian gesture for him to reunite with his family and seek medical care.

"We will continue to work actively to secure Mr. Bae's release, " Carney said, adding "Per our long-standing offer, we remain prepared to send Ambassador King to North Korea in support of that effort."

Donald Gregg, a former American ambassador to Seoul, arrived in Pyongyang on Monday for a visit. State Department spokeswoman Marie Harf said his visit does not represent the U.S. government.

Harf told reporters that U.S. civil rights leader Jesse Jackson had offered to travel to Pyongyang at the request of the Bae family. "We support the efforts, of course, of the family, but also of Reverend Jackson to bring Kenneth Bae home," she said.