The medics' fate has gripped Bulgaria

They were speaking at their first news conference since returning to Bulgaria on Tuesday, after more than eight years in prison in Libya.

"We have forgiven our torturers. But it doesn't mean we will not sue them. We have yet to decide," said Nasya Nenova.

Libya had sentenced the six medics to death for infecting children with HIV.

The five nurses and a Palestinian-born doctor, whose death sentences were later commuted to life imprisonment, had always maintained they were innocent.

All six were pardoned on their arrival by Bulgarian President Georgi Parvanov.

"I could forgive those who tortured us, because they were tools in the hands of others who issued the orders," said another of the nurses, Kristiana Valcheva late on Wednesday.

We can forgive, but we cannot forget Nurse Nasya Nenova Profiles: The medics

Ms Valcheva, Ms Nenova and Palestinian-born Dr Ashraf Alhajouj told the news conference that they were ready to testify in an investigation into 11 Libyan police officers, the Associated Press news agency reports.

Bulgarian prosecutors opened the case against them in January.

Ms Nenova described her time in prison as "horrifying", reiterating that she and the other captives had been tortured. But she did not give further details.

The Bulgarian government has thanked EU External Affairs Commissioner Benita Ferrero-Waldner and Cecilia Sarkozy, the wife of French President Nicolas Sarkozy, who helped negotiate the medics' release in Libya.

All six medics are said to be in good health.

The six retracted early confessions, saying they had been made under torture. Police officers accused of torturing them were acquitted in a separate trial in Libya.

The six medics were arrested in Benghazi in February 1999 along with 13 others, who were later released.