MISRATA, Libya — Iraqi commanders have been arriving from Syria, and the first public beheadings have started. The local radio stations no longer play music but instead extol the greatness of the Islamic State's self-proclaimed caliph, Abu Bakr al-Baghdadi.
When the Libyan arm of ISIS first raised the group's black flag over the coastal city of Sirte almost one year ago, it was just a bunch of local militants trying to look tough.
Today Sirte is an actively managed colony of ISIS, crowded with foreign fighters from around the region, according to residents, local militia leaders and hostages recently released from the city's main prison.
"The entire Islamic State government there is from abroad — they are the ones who are calling the shots," said Nuri al-Mangoush, the head of a trucking company based here in Misrata, about 65 miles west of the ISIS's territory around Sirte. Many of its employees live in Sirte, and five were jailed there recently.
As ISIS has come under growing military and economic pressure in Syria and Iraq, its leaders have looked outward.
One manifestation of the shift is a turn toward large-scale terrorist attacks against distant targets, including the massacre in Paris and the bombing of a Russian charter jet over Egypt, Western intelligence officials say. But the group's leaders are also devoting resources and attention to far-flung affiliate groups that pledged their loyalty from places like Egypt, Afghanistan, Nigeria and elsewhere. There are at least eight in all, according to Western officials, who spoke to the New York Times on condition of anonymity to discuss intelligence.
Of those, by far the most important is based in Sirte, a Libyan port city on the Mediterranean about 400 miles southeast of Sicily. Western officials familiar with intelligence reports say it is the only affiliate now operating under the direct control of ISIS leaders. In Libya, residents of Sirte and local militia leaders say the transformation of ISIS here has been evident for months.
"Libya is the affiliate that we're most worried about," Patrick Prior, the Defense Intelligence Agency's top counterterrorism analyst, said at a recent security conference in Washington. "It's the hub from which they project across all of North Africa."
The leadership of ISIS is now clenching its grip on Sirte so tightly that Western intelligence agencies say they fear the core group may be preparing to fall back to Libya as an alternative base if necessary, a haven where its jihadis could continue to fight even if it was ousted from its original territories.
Western officials involved in Libya policy say that the United States and Britain have each sent commandos to conduct surveillance and gather intelligence on the ground. Washington has stepped up airstrikes against ISIS leaders. But military strategists are exasperated by the lack of near-term options to contain the group here.
In Libya, where a NATO bombing campaign helped overthrow Col. Moammar Gadhafi four years ago, there is no functional government. Warring factions are far more focused on fighting one another than on taking on ISIS, and Libya's neighbors are all too weak or unstable to lead or even host a military intervention.
ISIS has already established exclusive control of more than 150 miles of Mediterranean coastline near Sirte, from the town of Abugrein in the west to Nawfaliya in the east. The militias from the nearby city of Misrata that once vowed to expel the group completely have all retreated.
Militia leaders and Western officials estimate that the group's forces in Libya now include as many as 2,000 fighters, with a few hundred in Sirte and many clustered to the east, around Nawfaliya. A flurry of recent bombings, assassinations and other attacks has raised fears that the city of Ajdabiya, farther to the east, is the group's next target. Its conquest could give ISIS control of a strategic crossroads, vital oil terminals and oil fields south of the city.
The group in Sirte has begun imposing the parent organization's harsh version of Islamic law on the city, enforcing veils for all women, banning music and cigarettes, and closing shops during prayers, residents and recent visitors said. The group carried out at least four crucifixions in August.
Last month it held its first two public beheadings, killing two men accused of sorcery, according to prison inmates who knew the men and a Sirte resident who said he witnessed the killings.
ISIS once called on Muslims everywhere to come to Syria and Iraq to join its self-declared caliphate. Its propaganda portrayed migration as all but a religious duty.
But the messages began to change as the state-building project came under increased military pressure in Syria. Increasingly, ISIS leaders began to focus more of their attention on the battle abroad, including in Libya.