Two Serbian Embassy staff members abducted in Libya in November were among nearly 50 people killed on Friday in U.S. air strikes on a suspected Islamic State training camp, Serbia's prime minister said.
U.S. officials said the site targeted in the strikes in Sabratha, western Libya, was a camp used by up to 60 militants, including Tunisian Noureddine Chouchane, blamed for two attacks on tourists in Tunisia last year in which dozens were killed.
Sladjana Stankovic, a Serbian communications officer, and Jovica Stepic, a driver, were taken hostage on Nov. 8 after their diplomatic convoy, including the ambassador, came under fire near Sabratha, a coastal city.
"It is officially confirmed that the two embassy staff were killed in air raids," Prime Minister Aleksandar Vucic told a news briefing in Belgrade. He described the deaths as "terrible collateral damage" and said Serbia had been close to securing their release.
The mayor of Sabratha, Hussein al-Thwadi, said the death toll from Friday's strikes had risen to 49.
It was the second U.S. air raid in three months against Islamic State in Libya, where the militants have exploited chaos following Muammar Gaddafi's 2011 downfall to build up a presence on the southern shores of the Mediterranean Sea.
On Saturday, Libya's attorney general said one of six wounded survivors told prosecutors those in the building that was hit were "members of Islamic State who came to Libya recently for training and then to carry out terrorist acts in Tunisia".
But Sabratha's mayor said the building was "just a house", adding: "The house was used for meetings and other acts but not training."
Serbian Foreign Minister Ivica Dacic said Serbian authorities had been negotiating the release of the two staff and "the kidnappers had a financial interest". But he said the demands had been "impossible" to meet by either the families or the government.
He said Serbia would send a protest note to Washington for not informing Serbian authorities of the raid.
U.S. officials have said they gave advance warning of the strikes to Libyan authorities, without specifying who they contacted.
Since 2014 Libya has had two competing governments, one based in Tripoli and the other, which has received international recognition, in the east.
Both sides are supported by loose alliances of former rebels and armed brigades. A unity government has been nominated under a United Nations-backed plan but has yet to win approval or move to Libya.
Western powers and the United Nations have been trying to reach out to armed factions to provide security for the unity government and tackle the threat from Islamic State militants.
The ultra-hardline group took control of Gaddafi's home town of Sirte last year and has carried out attacks in several other towns and cities.
Diplomats and foreign nationals have been targeted in the past for kidnappings, mostly for ransom or to demand the release of fighters being held by overseas governments. Islamist militants have also targeted foreigners.
Serbia has ties with both of Libya's governments.