(CNN) - North Korea rescinded an invitation for a U.S. ambassador to visit the country, to discuss the future of detained American Kenneth Bae, who has been held there since November 2012. It is the second time North Korea has canceled a visit by Washington's special envoy on North Korean human rights.

Over the weekend Bae was moved from a prison hospital to a labor camp. The American speaks about the difficulty of doing hard labor for eight hours a day, in a video released by a pro-north Korean newspaper based in Japan. But he had a message for his family.

"I have not lost hope and have not given up anything," Bae says in the video.

Here in the U.S., Kenneth Bae's sister had a message for North Korean leaders.



"We plead for mercy," Terri Chung told CNN's "The Lead with Jake Tapper."

"We understand that under D.P.R.K (Democratic People's Republic of Korea) laws that Kenneth has been convicted of crimes. He has made an apology. Our family has as well. He's served 15 months of his sentence," said Chung.

"We just plead with you to let him go and come back to his family," said Chung.

Reverend Jesse Jackson has been meeting with the Bae family, and has offered to travel to North Korea on a humanitarian mission to free Bae.

"We support the efforts of course of the family, but also of Reverend Jackson to bring Kennneth Bae home," a State Department spokesperson said Monday.

Jackson said he has been in touch with the State Department.

"We want to to be respectful of our government and respectful of the North Korean government," Jackson told CNN's "The Lead with Jake Tapper."

"I would hope that through some faith mission we would be able to break a hole in this wall, and the (freeing) of Mr. Bae would be such a good thing, because whenever prisoners are released, it always opens up some window of communication, and communication is the key to the kingdom," said Jackson.

For more of our interview with Terri Chung and Rev. Jesse Jackson, check out the video above.