The United States says it is "deeply disappointed" by North Korea's decision to rescind an invitation for an American envoy to visit and discuss the release of an imprisoned U.S. citizen.
White House spokesman Jay Carney said Monday that the United States remains prepared to send Robert King, a State Department expert on North Korean human rights issues.
King was planning to visit North Korea to discuss the release of imprisoned U.S. missionary Kenneth Bae.
The State Department said it also supports efforts by U.S. civil rights leader Jesse Jackson to help win Bae's release. It said Jackson has offered to travel to North Korea at the request of Bae's family.
It still is not clear what prompted the latest North Korean action. U.S. officials say it might be related to upcoming military exercises between the United States and South Korea.
Carney said the exercises should not be linked to Bae's case.
"We remind the DPRK that the U.S.-ROK military exercises are transparent, regularly scheduled and defense-oriented. These exercises are in no way linked to Mr. Bae's case, and we believe they know that," said Carney.
South Korea announced Monday that military drills with the United States will begin later this month.
Also Monday, North Korea received a different American delegation.
A group led by Donald Gregg, a former U.S. ambassador to Seoul, arrived in Pyongyang Monday at the invitation of the North Korean Foreign Ministry. Lynn Turk, another former U.S. diplomat, who held talks in Pyongyang in the 1990s, said they were there "to build bridges" between their countries. Neither Turk nor Gregg mentioned Bae.
U.S. Secretary of State John Kerry visits South Korea later this week with issues concerning Pyongyang likely to dominate the talks.
On Friday, the U.S. State Department said the 45-year-old Bae has been transferred from a hospital to a labor camp.
North Korea arrested Bae in late 2012 and later sentenced him to 15 years of hard labor on charges of trying to overthrow the government.
Calls for his release on humanitarian grounds have gone unanswered.
Bae was born in South Korea and emigrated to the United States with his parents and sister in 1985. He was living in China as a Christian missionary for about seven years before his arrest.
Within the last few years, he began leading small tour groups, mostly of American and Canadian citizens, into a "special economic zone" designed to encourage commerce in northeastern North Korea.