The United States is describing as "unacceptable" the convictions and death sentences handed down by a Libyan court against five Bulgarian medical workers and a Palestinian doctor accused of infecting Libyan children with the AIDS virus.

The United States had been closely following the case since the accused were arrested in 1999 and State Department spokesman Richard Boucher said that U.S. diplomats in Libya had made several appeals on behalf of the defendants since limited relations between the two countries were restored earlier this year.

Libyan prosecutors had accused the health workers of intentionally infecting more than 400 Libyan children at a Benghazi hospital with HIV contaminated blood. Defense lawyers said the infections resulted from poor sanitary conditions at the facility, before the accused persons arrived.

At a news briefing, spokesman Boucher said the case was a tragedy, but that the United States has been critical of what he said have been violations of the defendants' legal and human rights and finds the verdict pronounced by the Benghazi court to be "unacceptable."

"We recognize the great human tragedy that occurred in Benghazi and we extend our deepest sympathies to the families of 400 children who were infected with the HIV/AIDS virus," he said. "The death of over 40 children is also a devastating toll, but in this particular case, we note that the defendants have the right to appeal the verdict and we urge the government of Libya to take steps to resolve this case quickly."

Secretary of State Colin Powell discussed the pending verdict Wednesday with Bulgarian Foreign Minister Solomon Passy.

The spokesman reiterated a commitment Mr. Powell made to his Bulgarian counterpart that the United States will continue to follow that matter closely and do everything it can to bring pressure on the Libyan government, "to resolve this matter, so these people are released and can return home."

Mr. Boucher would not say whether the case would affect Bush administration decisions on removing remaining U.S. sanctions against Libya. Relations between the two countries have improved markedly since Libya renounced weapons of mass destruction last December.