Two Serbian nationals held hostage in Libya since November are believed to have been among those killed in Friday’s air strikes by US warplanes, the Serbian government says.
The jets targeted positions of the self-styled Islamic State group (IS) in the city of Sabratha.
The kidnapped Serbs, Sladjana Stankovic and Jovica Stepic, worked at the Serbian embassy in Libya.
Serbia is waiting for identification of the bodies, the foreign minister said.
Libyan authorities had yet to confirm the deaths, Ivica Dacic told a news conference in Belgrade, adding that “it was most probably true”. The news had come from foreign nationals.
Before the US air strike, the Serbian authorities had been trying to negotiate the captives’ release, Mr Dacic said.
But the kidnappers’ financial demands had been “impossible” to meet.
Ms Stankovic, a communications officer, and Mr Stepic, a driver, were seized on 8 November after their diplomatic convoy, bound for Tunisia, was rammed and fired on near Sabratha. Serbian ambassador Oliver Potezica escaped unharmed.
Top IS leaders ‘take refuge’ in Libya
Mr Davic said a protest note would be sent to Washington for failing to inform the Serbian authorities before the raid.
The dozens killed in Friday’s air strikes on the IS camp reportedly included Tunisian extremist Noureddine Chouchane.
He has been linked to two attacks in Tunisia last year, including one which killed 30 Britons in the beach resort of Sousse.
“We took this action against Sabir [Noureddine Chouchan] in the training camp after determining that both he and the Isil [IS] fighters at these facilities were planning external attacks on US and other Western interests in the region,” Pentagon spokesman Peter Cook said.
IS has been active in Libya for more than a year. The US estimates the group has up to 6,000 fighters there.
More than four years after the overthrow of former leader Muammar Gaddafi, Libya remains fragmented, fought over by a number of groups, including IS.
Different authorities rule over various regions, hampering efforts to find a unified national administration.
Islamic State militants in Libya
- IS jihadists seized a strip of land along Libya’s coast, around the city of Sirte, last year
- Libyan intelligence officials say foreign fighters and some IS commanders have relocated there from Iraq and Syria
- The US estimates the number of IS foreign jihadists at 4,000-6,000
- The largest groups are said to be from Tunisia, Egypt, Sudan and Iraq
- Recent recruitment has focused on sub-Saharan African countries
- It is not known how many of the jihadists are nationals of European countries
- IS militants have attacked Libyan cities, including Tripoli and Benghazi, and oil installations