The black-clad jihadist group Islamic State in Iraq and Syria (ISIS) made international headlines in June when it captured several Iraqi cities in quick succession, killed members of other sects or religions and imposed a harsh form of Shariah law.

Its notorious reputation has only grown in recent weeks, after the release of videos showing the beheadings of U.S. journalists James Foley and Steven Sotloff. ISIS has threatened to carry out more killings of Americans if the U.S. continues to target the group with airstrikes.

On Wednesday, U.S. President Barack Obama said the U.S. is determined to "degrade and destroy [ISIS] so that it’s no longer a threat, not just to Iraq but also to the region and to the United States."

Here's a closer look at how this group's reputation has grown in the last few months.

Who is this group and what do they want?

ISIS is a group of Sunni jihadists led by Abu Bakr al-Baghdadi, the nom de guerre of Awwad Ibrahim al-Badri al-Samarri.

The group, which was previously a rebel faction fighting the Bashar al-Assad regime in Syria, has in the last year amassed significant territory in eastern Syria and northern Iraq.

The group has denounced the Iraqi government, which under Prime Minister Nouri al-Maliki, a Shia, had alienated a large part of the country's Sunni population.

In June, the group announced that it had established a caliphate, or Islamic state, in the region that is governed by Shariah law. Baghdadi anointed himself the religious leader of the Islamic State, or IS, which is how the group now refers to itself. The group has called on Muslims worldwide to pledge allegiance to ISIS.

In an op-ed piece for Foreign Policy magazine, J.M. Berger writes that ISIS "wants what al Qaeda has – global terrorist credibility and the respect, support, and loyalty of the world's jihadi organizations."

What is its actual name – ISIS, ISIL or IS?

Since its emergence, the group has been referred to as the Islamic State in Iraq and al-Sham (ISIS), the Islamic State in Iraq and the Levant (ISIL) and simply the Islamic State (IS).

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Territorial gains made by ISIS in Iraq and Syria have inspired many jihadis from around the world to join the cause. (Reuters)

While the disparity between "ISIS" and "ISIL" is merely a difference in the transliteration of the Arabic word for "Syria," the use of "IS" is a political statement, says Kamran Bokhari, vice president of Middle Eastern and South Asian affairs for the Texas-based geopolitical intelligence firm Stratfor.

He says that every Islamist around the world dreams of an Islamic state, and by calling itself IS, Baghdadi's group has laid claim to this elusive entity.

An Islamic state "is what every Islamist wants, and this one group has cleverly appropriated this discourse," says Bokhari, author of Political Islam in the Age of Democratization. (Most media outlets, including the CBC, continue to refer to the group as ISIS.)

Does it have any allies?

ISIS was originally an offspring of al-Qaeda until this past spring, when al-Qaeda leader Ayman al-Zawahiri publicly disowned the group, largely because it did not follow orders in the anti-Assad insurgency in Syria. In fact, ISIS ended up in open conflict with the Nusra Front, another al-Qaeda affiliate.

ISIS has subsequently said that al-Qaeda's tactics in the global jihad have been largely ineffective, and that through its merciless tactics, ISIS has achieved the one thing that al-Qaeda has not: the establishment of an Islamic state.

J.M. Berger writes that "very few establishment al Qaeda supporters and clerics have come down in favour of the Islamic State."

He cites a couple of exceptions, including Mamoun Hatem, a prominent figure in Al-Qaeda in the Arabian Peninsula, and Abu Bakar Bashir, a cleric in the former Southeast Asian jihadi group Jemaah Islamiyah.

But for the most part, "the elders in the jihadist hierarchy see the Islamic State as an aberration," says Bokhari.

He says that as a result, ISIS has few allies. Among them are partners with similar goals who may not share the group's philosophy. Bokhari says these include some Iraqi tribal leaders and former members of Saddam Hussein's Baath party, who would all like to see government control wrested away from Iraq's majority Shia.

On how many fronts is ISIS fighting?

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Kurdish peshmerga fighters are only one of several factions fighting ISIS in Iraq. (Youssef Boudlal/Reuters)

Given the dearth of allies and the fact that much of its captured territory is not contiguous, ISIS finds itself fighting on numerous fronts in Iraq and Syria, says Bokhari.

In Syria, they are battling the Assad regime, moderate Syrian rebel groups, as well as fellow jihadists such as the Nusra Front.

In Iraq, they must contend with the Iraqi army, Shia militias, moderate Sunni groups, Kurdish peshmerga fighters — as well as U.S. airstrikes.

Is ISIS expanding?

In addition to the ground it has captured in Syria and Iraq, Bokhari says that ISIS has a "non-trivial presence" in Lebanon and Jordan. But he warns about overestimating the group's reach, saying that ISIS has become very adept at psychological operations.

"All it takes is for a few people to raise the ISIS flag somewhere after Friday prayers. That creates the idea that this group is expanding, which feeds into the media frenzy and the global panic," says Bokhari.

"The reality is that they went back into Iraq in June because they had reached a ceiling in Syria," where they had come into direct conflict with many of the jihadist groups that they had once fought alongside.

How does the threat of more U.S. airstrikes affect ISIS's stature?

While ISIS has claimed that they released the beheading videos as a deterrent against further U.S. airstrikes, Bokhari believes the group is actually taunting the U.S. and its allies into more attacks.

By painting the West as the aggressors, ISIS gains greater legitimacy, not only among its ardent followers, but more moderate Muslims who may be on the fence about joining them.

"My view of [the beheading videos] is that they are trying to bait the U.S. in order to rally more people to their cause."

British journalist and academic Sunny Hundal is one of many commentators who share this perspective. In a piece for the New Statesman magazine, Hundal wrote that while Saddam Hussein's army "barely put up a fight against American troops" when the U.S. invaded in 2003, "the warriors of Islamic State would relish fighting them on their holy land."