Islamic State terrorists may be hiding among Mediterranean boat migrants, Libyan Prime Minister Fayez Serraj warned in a Wednesday interview with Italian newspaper Corriere della Sera.
Italy said last week it was investigating links between migrant smuggling and Islamist groups. It is unclear whether Islamic State either makes money off the people-smuggling business or uses it as a covert form of transport.
"The Islamic State is a very dangerous organization. It will use every means to send its militants to Italy and Europe," Serraj told the newspaper.
"I would not at all be surprised to discover that its men are hiding on boats headed towards your shores. We have to tackle this problem together," he added.
The Libyan leader called on the international community to help stabilize migrants' countries of origin, and said he wanted to "find a way" to repatriate those who arrive in Libya en route to Europe.
Serraj's interview came as forces aligned with his United Nations-backed government said they had lost contact with one of their warplanes during operations against Islamic State in Sirte, its last stronghold in Libya.
Islamic State, via its Aamaq outlet, reports its fighters shot down a warplane over the city, killing its pilot.
The forces fighting the extremists also said they had gained further positions in street fighting inside Sirte.
Serraj, who asked last week for US airstrikes against Islamic State in Sirte, said he expected victory against the extremists in "probably a few weeks, rather than months."
He also insisted there was no need for greater international help.
"Our men can do it on their own, once they get air support," Serraj said, specifying that he had asked for "very surgical and limited in time" US raids. "We don't need foreign troops on Libyan soil," he added, reiterating comments he had made previously.
Islamic State controlled a more-than 250-kilometre stretch of the Libyan coast before forces aligned with Serraj's government began operations against it in May.
Analysts said the extremist organization had sent senior figures to Libya to build up its power there as its main territory in Syria and Iraq came under pressure from Kurdish and Iraqi government forces backed by an intensive US-led air campaign.
The militants took advantage of conflict between two rival governments based in western and eastern Libya, a split which Serraj's nascent unity administration has not yet fully overcome.
Those ongoing divisions were reflected Wednesday in a joint statement from France, Germany, Spain, the United States, Italy and Britain expressing concern about rising tensions around the Zueitina oil terminal, which lies on Libya's central-eastern coast.
According to local newspaper the Libya Herald, forces loyal to eastern Libyan military commander Khalifa Haftar have recently arrived near the port, leading to rumours they might try to capture it from a guard force which is currently aligned to Serraj.
Haftar is widely thought to be behind the failure of the eastern Libyan authorities to back Serraj's unity government. His allies have objected to a clause in the UN-backed peace agreement that would give the government control over the military.
Serraj told Corriere della Sera that "our dialogue with General Haftar has never stopped" but that "military commanders must obey their country's politicians."
In a statement released by the French Foreign Ministry, the Western governments expressed their support for Serraj's government and called for all energy installations to be put back under its control.
"The national accord government should work with the National Oil Corporation to relaunch petroleum production in order to rebuild the Libyan economy," the statement said.
Fighting between rival militias since the fall of former dictator Moamer Gaddafi in 2011 has thrown Libya into political and military chaos. There is rising concern among Western governments that the country is becoming a hotspot for jihadists and potential terrorists.