The foreign policy spokesperson for the opposition Green Party, Bodil Ceballos, told Radio Sweden that she was not surprised by the revelations.
"I'm not surprised that they have been talking in these terms but I am surprised that they have been talking like this to diplomats from another country."
The Green MP went on to say that the reported return agreement was in breach of the right to asylum.
"I think it is a way of breaking the way of asylum to mix internal problems with the right of asylum. These people are in need of protection. Immigration authorities should judge asylum applications on each person's need for protection rather than on a policy. "
Bodil Ceballos says she plans to file a complaint against Bildt and Billström with parliament’s Committee on the Constitution.