by Priyanka Boghani

The Islamic State of Iraq and Syria extended its geographic influence on Monday when Egypt’s most deadly militant outfit pledged obedience to ISIS’ self-declared caliph, Abu Bakr al-Baghdadi.

The group, Ansar Beit al-Maqdis, operates in Egypt’s Sinai Peninsula and is responsible for the deaths of hundreds of Egyptian security forces within the last two years. Formed in the wake of Egypt’s Arab Spring, the group has attacked both Egyptian and Israeli targets.

While Ansar Beit al-Maqdis may be the deadliest group to pledge allegiance to ISIS in the last few months, it isn’t the first. In October, extremist militants in control of the Libyan city of Derna likewise pledged allegiance to Baghdadi, giving ISIS its first toehold in the turbulent country. Activists in Libya said a new “emir” was named to lead the city, and government buildings were converted into offices of the so-called Islamic State, according to the Associated Press.

[Update: On Thursday, ISIS released an audio recording purportedly of Baghdadi, accepting the new pledge.]

Earlier this year, lesser-known Islamic extremist groups such as Abu Sayyaf in the Philippines, and Indonesia’s Jama’ah Ansharut Tauhid also voiced their support for ISIS. Similarly, small groups of individual fighters from two of Al Qaeda’s most powerful branches in Yemen and North Africa have defected to ISIS.

For ISIS, the growing support from militants operating beyond Syria and Iraq has helped strengthen the group in important ways. ISIS has sought such pledges of allegiance to bolster its reputation as the world’s leading jihadist group. More worrying, say global terror experts, it has increased its ability to both recruit foreign fighters and carry out attacks in territories far from its self-declared caliphate.

“The concern is that some of these groups will start carrying out attacks on behalf of the Islamic State,” according to J.M. Berger, co-author of the forthcoming book, ISIS: The State of Terror. “What we’ve seen with [Ansar Beit al-Maqdis] is they seem to be emulating some of the Islamic State’s tactics. Another concern is that the very, very brutal and very active pace that the Islamic State sets will spill over in some of these other areas.”

In a grim illustration of that point, three young activists were found beheaded in the Libyan city of Derna on Tuesday.

For now, at least, it remains unclear what tangible benefits such groups gain from pledging allegiance to ISIS, but at least one factor could be financial support. With the millions it has made through oil production and kidnapping ransoms, ISIS has more money than it can spend, according to Berger, who noted recent reports of ISIS offering money in exchange for pledges.

“What I would be looking for is evidence that when these groups pledge to ISIS, they’re going to get funding to step up their global operations,” Berger said.

Such benefits aside, pledges of support for ISIS may be splintering the global jihadi movement more broadly, according to Berger.

A recent, prominent example was when a spokesman for the Pakistani Taliban and five commanders pledged loyalty to ISIS’ leader, saying, “I will obey and listen to [Baghdadi’s] every instruction, no matter what the circumstances and whether I like it or not.” The declaration led the Pakistani Taliban to fire the spokesman and all five commanders, and then restate its oath of allegiance to Mullah Omar, the Taliban leader that Al Qaeda recognizes as “emir.”

“From the perspective of the West, in some ways this is playing out favorably to us in that ISIS is causing dissent within existing jihadi organizations,” Berger said. “What we don’t want to see is ISIS winning this competition with Al Qaeda. We don’t want to see ISIS become the standard bearer for global jihad.”