Tripoli, Libya ? Five Bulgarian nurses and a Palestinian doctor at the center of intense international negotiations won a reprieve on Sunday, when Libya’s highest court overturned their death sentences on charges they deliberately infected children with AIDS.

The United States and European Union have made it clear that their future relations with Moammar Gadhafi depend upon the outcome of the case, but the Libyan leader faces high emotions at home, where relatives of the infected children angrily protested Sunday’s decision in Tripoli. Some set fire to tires and clashed with police. Four demonstrators were arrested.

The Libyan government issued no immediate statement on the court ruling. In Washington, State Department spokesman Justin Higgins said “our understanding is that this decision is a positive development since it removes the risk of the death sentence being carried out.” The nurses and doctor are widely expected to receive lighter sentences in a retrial ordered by the supreme court.

Its ruling came three days after U.S., European and Libyan negotiators reached a deal to set up a fund to help families of the 426 children infected with HIV in the 1990s. About 50 of the children have died, according to a lawyer for the families.

The United States and European Union had accused Libya of trumping up the charges to divert attention from poor hygiene at its hospitals. The court’s chief judge Sunday described “irregularities” in the case.

Gadhafi is eager to improve ties with the West and was believed to be looking for a face-saving way out.

The health workers were accused of deliberately infecting the children at a Benghazi hospital as part of an experiment. The workers said they were tortured to extract confessions.