|Egypt is bombing Islamic State targets in its stronghold of Derna|
It has gained a foothold in key towns and cities in the mostly lawless North African state, prompting Egypt - seeing itself as the bulwark against Islamists in region - to launch air strikes against the group.
Last August I reported on IS in Libya, and in September I reported that IS was popping up all over the place. As limited in numbers as they are I think it will be impossible to stamp them out. There is too much money behind them and the extreme ideology is a literal adherence to the Quran. There may be ebbs and floes in the IS tide, but eventually it will become a tsunami.
After the two war-ravaged Middle Eastern states, IS has launched its most high-profile attacks in Libya, bombing an upmarket hotel in the capital, Tripoli, in January, and releasing a video earlier this month showing the beheading of 21 Egyptian Coptic Christians it had kidnapped.
For UK-based Libyan academic, Mohamed Ahdash, the emergence of IS affiliates in Libya is not surprising.
"There is a study which shows that after Saudi Arabia, most of the fighters who went to Syria were from Libya," he told the BBC.
'Magnet for African jihadists'
Libya's UN-backed government believes the fighters are now returning, following a shift in IS thinking to promote local jihad, and are under the command of a Tunisian named Abu Talha.
|A fighter of Libya's Fajr Libya group (Libyan Dawn) fires his gun during clashes|
in the hill village of Kikla, southwest of Tripoli on 21 October 2014
Libya descended into anarchy after the fall of Col Gaddafi
|A Libyan woman walks past the rubble of a building in the Mediterranean|
city of Sirte on 13 October 2012. The militants have built a presence in Sirte,
which was heavily bombed during the campaign to oust Gadaffi
Moreover, Libya is rich in oil and earlier this month, gunmen claiming to represent IS raided a French-run oil facility in al-Mabruk, south of Sirte city, killing at least 11 guards.
Libyan oil is a potentially lucrative source of funding for IS, though it will find it difficult to export it because of the foreign navies patrolling the Mediterranean coast.
Mr Ahdash says Libya has become a magnet for jihadis from other parts of Africa - especially those who fled northern Mali after a French-led military operation recaptured territory from them in 2013.
"They are under one umbrella, but they are very different and very divided. It is difficult to work out who is who," he says.
He says Islamists had a presence in Libya during Col Gaddafi's rule, but they were heavily suppressed.
|The late Strongman Col Muammar Gadaffi|
But what surprises him, Mr Ahdash says, is that they have secured a presence in Sirte, the birthplace of Col Gaddafi, which had been seen as hostile towards Islamists.
He says either foreign jihadists have infiltrated the city or Gaddafi loyalists, including military officers, have joined the militants, just as they did in Iraq after Saddam Hussein was overthrown by US-led forces in 2003.
"I'm worried that could happen in Libya; that there could be a marriage of interest," says Mr Ahdash, pointing out that Ahmed Gaddafi al-Dam, an influential cousin of the former ruler, has publicly hailed IS as "pure".
|An image posted online by militants who claim to be part of the Islamic State|
group showing them destroying statues in Derna - 1 February 2015
"Most Libyans are moderate Muslims, and they hate Daesh," Mr Ahdash told the BBC, referring to the name by which IS is known in the Arab-speaking world.
|A Coptic clergyman shows a picture of a man whom he says is one of the|
Egyptian Coptic Christians purportedly murdered by Islamic State (IS)
group militants in Libya. Egypt intervened after its nationals were killed.
IS-linked fighters operate in Tripoli, the south-western region of Fezzan, and the eastern region of Barqa, which includes Benghazi and Derna.
However, Thomas Joscelyn, senior editor of the Long War Journal, says that while IS has grown in Libya, its strength should not be exaggerated.
"These zones are more aspirational than they are real," Mr Joscelyn told Foreign Policy.
Even if IS control in Libya is limited to a few small areas, it still has the potential to make the country's desperate situation even worse, threatening regional stability.