There are currently 97 Yemenis being held at Guantanamo, making up almost half the 210 detainees who have yet to be relocated.
The impending release has spawned fears that Yemen would be unable to effectively monitor and rehabilitate returnees.
"I believe they will be involved in terrorism that will cost American lives," Republican Congressman Frank Wolf (R-VA) was quoted as saying in the Post.
Negotiations with Yemen are said to have included Stephen R. Kappes, the deputy director of the CIA. The agency declined to comment.
On Tuesday, the White House said it was moving a "limited number" of detainees to Thomson Correctional Center in Illinois.