Fresh efforts are under way in Libya to resolve the case of five Bulgarian nurses and a Palestinian doctor who are under sentence of death.
The six medics say their confession were obtained under torture
The six were convicted in 2004 of infecting 426 Libyan children with HIV, the virus that causes Aids. They have insisted they are innocent.
Germany's foreign minister and the EU's external relations commissioner are in Libya to try to secure their release.
A son of Libyan leader Muammar Gaddafi said a solution may be near.
Saif al-Islam said the European initiative was "positive".
"We are in the last mile of a marathon race and we are in the most difficult stage," he told reporters.
He added that a decision to end the crisis would have to be made by the Libyan judiciaries and families of the victims.
He was speaking after talks with visiting EU External Relations Commissioner Benita Ferrero-Waldner and German Foreign Minister Frank-Walter Steinmeier.
A spokesman for the families said that any agreement must guarantee the expenses of the families, free treatment in European hospitals and the payment of indemnities.
The six have already spent eight years in prison, awaiting trial and following their conviction.
During a retrial in 2006, they said prosecution evidence had been obtained under torture.