ISIS leader Abu Bakr al-Baghdadi
ISIS leader Abu Bakr al-BaghdadiReuters

The Islamic State (ISIS) group's "caliphate" enters its second year Monday with the jihadists expanding their territory in Syria and Iraq and their global reach by claiming attacks in Tunisia and Kuwait.

The extremist group headed by Abu Bakr al-Baghdadi announced on June 29, 2014 that it was reviving a form of Islamic government known as the "caliphate," pledging it would "remain and expand."

In the year since, the group has gained more territory in Syria and Iraq despite an attempted fightback supported by a US-led coalition air campaign.

It has also attracted a string of affiliates - in Egypt, Libya, Yemen, Pakistan and elsewhere - and sought to project fear on an international scale.

Last week, the group claimed responsibility for the attack in Tunisia in which 38 people, mostly foreign tourists, were killed at a seaside resort. And it said it was behind a suicide bomb attack against a Shi'ite mosque in Kuwait that killed 26 people.

ISIS also appeared to be the inspiration for an attack in France in which a man rammed his van into a gas factory and beheaded his boss.

"It's not clear that these actions are centrally planned or coordinated by ISIS," said Yezid Sayegh, a senior associate at the Carnegie Middle East Center think tank.

"That said, we may be seeing the start of a long campaign conducted by ISIS members or sympathizers who have been trained and then sent back home to their countries to take their own initiative in planning and conducting attacks, depending on their abilities, resources, and opportunities."

Thousands murdered by ISIS

Already, ISIS has inspired fear and horror with its rule over territory in Syria and Iraq, where mass killings and brutal executions have become its hallmarks.

The group controls about 50% of Syria's territory, though much of it is uninhabited, and perhaps a third of Iraq.

In Syria alone, it has executed more than 3,000 people in the year since announcing its "caliphate," the Syrian Observatory for Human Rights monitoring group said on Sunday.

Nearly 1,800 of them were civilians, including 74 children, it said.

They include more than 200 people killed in the Syrian Kurdish town of Kobane during an ISIS attack last week, and over 900 members of the Sunni Muslim Shaitat tribe who were killed in 2014 after opposing the jihadist group.

There are no reliable figures in Iraq, but the group is believed to have executed thousands there, including as many as 1,700 mostly Shi'ite recruits at the Speicher military base near Tikrit.

Thousands more have died battling ISIS in Syria and Iraq, including Syrian rebels and government forces, Kurdish fighters in both countries, and Iraqi government troops and Shi'ite militias.

But few of those forces have had much success against the group, with the Iraqi army in particular facing criticism for abandoning territory to ISIS during a push by the jihadist group in mid-2014.

Military, political failures

Iraqi government forces have "no clear command structure," said Zaid al-Ali, author of "The Struggle For Iraq's Future."

"Clearly Baghdad should have enough forces at its disposal to control territory, but not all the anti-ISIS forces take their instructions from Baghdad," he added. "Some operate as they please, some take instructions from elsewhere."

In Syria meanwhile, only Kurdish forces backed by the US-led coalition have been able to effectively tackle the group, with analysts saying opposition forces and the regime appear to lack the weapons or the resolve to fight the jihadists.

Even the anti-ISIS coalition, which is carrying out air strikes in Syria and Iraq and training Iraqi troops on the ground, has had limited success.

It has helped ground forces push ISIS from Kobane and Tal Abyad in Syria, and Tikrit and Diyala province in Iraq. But the group has continued to score shocking victories, including the recent capture of Syria's ancient town of Palmyra and the taking of the Iraqi city of Ramadi in mid-May.

"The international mobilisation against Daesh has been minimal," said Sayegh, using the Arabic acronym for the group.

"But it may be that they cannot do more, because the return of 150,000 US troops to the battlefield is out of the question."

Ultimately analysts say ISIS's success is as much the result of political problems as it is military shortcomings.

ISIS has emerged because of "the failure of Syria and Iraq and the sectarian divisions in them, as well as corruption and decades of authoritarian rule," Sayegh said.

AFP contributed to this report.