WASHINGTON: North Korea has rescinded an invitation for a senior U.S. official to visit Pyongyang to seek the release of imprisoned U.S. missionary Kenneth Bae, a State Department official said on Sunday, adding civil rights activist Jesse Jackson had offered to go to Pyongyang to try to free Bae.

"We are deeply disappointed by the DPRK (North Korean) decision - for a second time - to rescind its invitation for Ambassador (Robert) King to travel to Pyongyang to discuss Kenneth Bae's release. The DPRK announced publicly in May 2013 it would not use the fate of Kenneth Bae as a political bargaining chip," the official said.

"At the request of the Bae family, Reverend Jackson offered to travel to Pyongyang on a humanitarian mission focused on Bae's release. We support the efforts of the Bae family and Reverend Jackson to bring Bae home," the official said.

North Korea's official KCNA news agency has not reported on the latest invitation to King or why it was rescinded but said on Monday a retired U.S. diplomat had arrived in its capital, Pyongyang.

The retired diplomat, Donald Gregg, who was U.S. ambassador to South Korea in the late 1980s and 1990s and who has advocated dialogue with North Korea, arrived for a visit with a group, KCNA said. It did not elaborate.

Earlier, the U.S. official referred to U.S.-South Korean (Republic of Korea) military exercises, which North Korea (the Democratic People's Republic of Korea) opposes.

"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," the official said. "We again call on the DPRK to grant Bae special amnesty and immediate release as a humanitarian gesture so he may reunite with his family and seek medical care."

The United States and South Korea will hold their annual joint military drills from Feb. 24 to April 18, the combined forces command that oversees the allies said, adding it had notified Pyongyang of the plan.

The official said the United States remained prepared to send King to North Korea to seek Bae's release.

Jackson could not immediately be reached and his office did not respond to requests for comment.

Bae, a 45-year-old Korean-American, has been held for more than a year in North Korea after being sentenced to 15 years of hard labor on charges of trying to overthrow the state.

The U.S. State Department said on Friday Bae 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.

North Korea rejected an offer for King, the U.S. special envoy for North Korean human rights issues, to visit Pyongyang to discuss Bae's case last August.

Bae said in an interview with a pro-North Korea newspaper published in Japan last week that a Swedish Embassy official had visited him and told him King would visit as early as Monday and by the end of the month at the latest.

Bae told the Choson Sinbo newspaper the United States had offered to send Jackson, but North Korea had instead approved the visit by King.

Jackson, who twice sought the U.S. presidency, secured the freedom of a U.S. Navy pilot held by Syria in 1983 after meeting with the late Syrian president Hafez al-Assad, father of the current president, in Damascus.

He commented last month on Twitter on controversial visits to North Korea by retired basketball star Dennis Rodman, saying "@dennisrodman ping pong diplomacy worked in China, and Basketball seems to work in North Korea."

In a television interview, he called Rodman's visits "illuminating" about North Korea.

"I would not confuse the role of Dennis Rodman and basketball and the Globetrotters in the Soviet Union and ping pong in China with serious diplomacy, but entertainment does have an interesting way of illuminating," he told CNN.

"Ping pong diplomacy" was credited with playing a role in the United States normalizing relations with China in the 1970s. It was used to refer to a tour of American table tennis players for a series of exhibition matches in China in 1971.

Bae's sister, Terri Chung, told Reuters on Friday that Bae had been held in a labor camp from May 14 last year until Aug. 5, when he was moved to hospital. She said the family did not know where the camp was, but that it was far from Pyongyang and Bae was working eight hours a day, six days a week.

Chung said her brother suffered from a variety of health issues, including diabetes, an enlarged heart, kidney stones and severe back pain and that his family was very concerned about his health.

Bae has acknowledged being a missionary and has said he conducted religious services in the North, one of the world's most isolated states and long hostile to Westerners advocating religious causes.