Who's Behind The Paris Massacre? It's Too Soon to Tell

No group has yet taken responsibility for the Paris attacks that have killed at least 140 people on Friday. American cable news networks like CNN and Fox News are openly speculating that the Islamic State is responsible, but the group has yet to release a statement claiming involvement.

At first glance, the attack today in Paris could be interpreted as IS retaliation for two major losses on Thursday and Friday. A joint US-Kurdish offensive forced IS to retreat from the Iraqi city of Sinjar, and a US drone took out a militant who is most likely Jihadi John, the executioner responsible for the beheadings featured in the gruesome propaganda videos the terrorist group is known for.

But terrorism experts were wary to ascribe causation and noted that to plan and coordinate such an attack would require time and resources, and could not possibly be linked to events that took place on the same day. At least seven, possibly eight, attackers have been killed in Paris according to law enforcement sources, indicating a well-planned action that would have required a fairly intricate plan to pull off.

Related: In The Streets of Paris Under Attack

Still, as noted terrorism researcher Charlie Winter pointed out, chatter among IS sympathizers online indicates a lot of enthusiasm for the attack.

Before anyone - especially tabloids - suggests it, #Paris is not #IS retaliation for #Emwazi. The attacks will have taken weeks to plan.

— Charlie Winter (@charliewinter) November 14, 2015

The last major terrorist incident in France, the January shooting at the offices of the cartoon magazine Charlie Hebdo, was eventually linked to Al Qaeda's affiliate in Yemen, AQAP. And there's no way of being sure at this juncture whether IS, AQAP, or some other group was involved in the Friday carnage.

Will McCants, the author of ISIS Apocalypse, pointed out that if the attack had indeed been ordered by IS, it would mark a significant shift in the group's strategy.

If the Paris attack and those in Egypt and Lebanon were all directed by ISIS Central, they represent a major shift in its global strategy.

— Will McCants (@will_mccants) November 14, 2015

So far, IS has not expended serious resources mounting spectacular terrorist attacks in Western countries. But over the past few weeks, IS has taken responsibility for a smattering of attacks far from its base of operations in Syria in Iraq: The likely bombing of a Russian airplane in the Sinai, a suicide attack in Lebanon, and on Friday, a twin bombing in Baghdad.

Related: While Sympathy Pours in on Social Media, Some Celebrate Paris Attack

Bill Roggio, a terrorism expert at the Long War Journal, pointed out the similarities between today's attack and the 2008 terror attack in Mumbai, India, where a Pakistani jihadist group launched a series of coordinated shootings and bombings across the city.

At least 7 sites in Paris hit in attacks. Again, planned in advance. This attack appears to be very similar to Mumbai, Nov. 2008.

— Bill Roggio (@billroggio) November 14, 2015

That model of terrorism — a multi-pronged attack, involving heavily armed gunmen who target non-military facilities — could be executed by any number of groups. Indeed, it's even within the capabilities of an unaffiliated, lone-wolf group of terrorists.