Two Serbian embassy staff members abducted in Libya in November are believed to have been killed on Friday in US air strikes on a suspected Islamic State training camp, Serbia's foreign minister said on Saturday.

Sladjana Stankovic, a communications officer, and Jovica Stepic, a driver, were taken hostage on Nov. 8 after their diplomatic convoy, including the ambassador, came under fire near the coastal city of Sabratha.

‘We are expecting identification of the victims, so formally we cannot confirm the information,’ Foreign Minister Ivica Dacic told a news conference.

Dacic said Serbian authorities had been negotiating the release of the two prior to the attack.

‘The kidnappers had a financial interest,’ Dacic said, adding that 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.

More than 40 people, probably including a militant connected to two deadly attacks last year in neighbouring Tunisia, were killed in Friday's strikes by US warplanes in western Libya.

Diplomats and foreign nationals have been targeted in the past for kidnapping, mostly for ransom or to demand the release of Libyan fighters being held by overseas governments. Islamist militants have also targeted foreigners.

Serbia has ties with both the internationally recognised Libyan government based in the eastern town of Tobruk and with the self-declared authorities in the capital Tripoli.