Libya's highest court has again rescheduled a ruling on the death sentences of six foreign health workers accused of infecting children with HIV.
Bulgaria's President Parvanov has visited the nurses in Libya
It was to hear the appeal of five Bulgarian nurses and a Palestinian doctor at the end of January 2006, but will now hear it on 25 December.
Reports of the new date came from Bulgaria's foreign ministry. Tripoli has not confirmed the rescheduling.
Human rights groups have said the medics were tortured in detention.
The nurses and doctor were sentenced to death in 2004, in a case which has drawn condemnation from Europe and the United States.
The court was to have heard their appeal last month, but postponed the hearing to give the defence more time to prepare.
There has been no word as to why the appeal was moved forward again, but Bulgarian President Georgi Parvanov said there had recently been "calm and even positive statements" from Libya and the association of parents of children who died of Aids.
Bulgaria has refused a Libyan demand for payment to secure the release of the nurses, who have been held since 1999.
It says that to pay any money would be to accept the women's guilt - something it has refused to do.
However, it has hinted at offering humanitarian assistance to the children in an attempt to resolve the situation.
The nurses and a Palestinian doctor were detained following the outbreak at a hospital in the eastern city of Benghazi.
Of roughly 400 children affected, about 50 have since died.
The Libyan government has faced intense pressure from Europe and the US to free the nurses, amid accusations they were wrongly convicted.
Experts, including Luc Montagnier, a co-discoverer of the virus, say the Aids epidemic broke out because of poor hygiene at the Benghazi hospital where the incident took place.
They also say the infection spread before the nurses' arrival at the hospital. Despite the US and others condemning the convictions, Tripoli has so far refused to bow to pressure.