The “unprecedented” spread and brutality of ISIS, its strength in recruiting foreign fighters, messaging and its ability inspire lone wolf attacks have helped the group supplant al Qaeda as the leading global terrorist group, said the State Department’s annual terrorism report. The report says both are adapting their tactics in ways which are more brutal and harder to trace.

“The prominence of the threat one posed by core al Qaeda diminished in 2014,” the report found. In addition to significant losses of its core leadership in Afghanistan and Pakistan, it noted that “AQ leadership also appeared to lose momentum as the self-styled leader of a global movement in the face of ISIL’s rapid expansion and proclamation of a Caliphate.”

The report, obtained by CNN, is expected to be officially released later Friday.

The number of terrorist attacks in 2014 increased 35% over the previous year, but were more heavily concentrated in a handful of countries. More than 60% of all attacks took place in five countries — Iraq, Pakistan, Afghanistan, India and Nigeria — according to the National Consortium for the Study of Terrorism and Responses to Terrorism at the University of Maryland, which compiles statistics on worldwide terrorism.

By a wide margin, the highest number of attacks, fatalities and injuries took place in Iraq, coinciding with the expansion of ISIS.

An 81 percent increase in fatalities last year was, in part, a result of exceptionally lethal attacks. Twenty-four Americans died last year in terrorist attacks, mostly in Afghanistan, Somalia and Jerusalem.

The report cited increasingly aggressive tactics and brutality by terrorist in their attacks, beheading, crucifixions and mass causalities. Kidnapping and hostage-taking has also increased over the past year.

The report singled out the Nigeria-based Boko Haram as sharing ISIS’ “penchant for the use of brutal tactics,” such as stonings and enslaving children. Although ISIS was responsible for the greatest amount of attacks last year, it was a close second to Boko Haram in number of fatalities.

The U.S. also recognized ISIS’ prowess in using social media to spread its message and recruit followers, noting the group “has been adroit at using the most popular social and new media platforms (YouTube, Facebook and Twitter) to disseminate its messages broadly.”

ISIS’ initial publication of online propaganda is followed by near instantaneous reposting, follow-up links and translations into additional languages, the report found, adding that the groups’ members answered real-time questions from would be members about how to join the group.

The report called the Syrian civil war a “significant factor” for many of last year’s terrorist attacks worldwide. Despite the standing up of a worldwide anti-ISIS coalition and a UN Security Council resolution making the travel of foreign fighters to and from conflict zones illegal, more than 16,000 foreign terrorist fighters traveled to Syria in 2014, according to the report — most of them to join ISIS.

“The rate of foreign terrorist fighter travel to Syria … exceeded the rate of foreign fighters who traveled to Afghanistan and Pakistan, Iraq, Yemen or Somalia at any point in the last 20 years,” the report said.

Weak and failed governments were blamed for providing an “enabling environment” for the emergence of extremist radicalism and violence — not only in Syria and Iraq, but also in Yemen and Libya, where jihadi groups have flourished.

The U.S. is “deeply concerned” about the growth of ISIS beyond Syria and Iraq and the birth of self-proclaimed affiliates, the report found, particularly in Libya, Egypt and Nigeria. It acknowledged questions remain about the meaning of such affiliates – whether they represent a command relationship or the groups simply share “merely opportunistic relationships” with ISIS.

Although al-Qaida’s leadership has been weakened, the report said the group “continued to serve as a focal point of inspiration” for its worldwide network of affiliates, such as AQAP in Yemen, al-Nusra Front in Syria and al-Shabaab in Somalia.

Even as it negotiates with the U.S. and other world powers on a nuclear deal, the report found Iran’s sponsorship of terrorism worldwide last year remained “undiminished.”

The report pointed to Tehran’s support for Palestinian terror groups, its proxy Hezbollah and several groups in Iraq and accused Tehran of “prolonging the civil war in Syria, and worsening the human rights and refugee crisis there,” suggesting neither improved relations with the west as a result of nuclear negotiations, nor Iran’s reformist President Hassan Rouhani has moderated Iran’s foreign policy agenda in the region.

The report said Iran used its Islamic Revolutionary Guard Corps-Qods Force “to implement foreign policy goals, provide cover for intelligence operations, and create instability in the Middle East.” It called the Qods force Iran’s “primary mechanism “for cultivating and supporting terrorists abroad.”

Tehran increased its assistance to Iraqi Shia militias, primarily to combat ISIS. But some of those groups “have exacerbated sectarian tensions in Iraq and have committed serious human rights abuses against primarily Sunni civilians,” the report said.

It did note, however that despite Shia militias have declared opposition to the return of U.S. troops to Iraq to fight ISIS and have threatened attacks, “they refrained from launching strikes against U.S. personnel in 2014.”

Although the report only covers 2014, US officials said there is nothing to indicate Iran’s policy has changed as the June 30 deadline for a nuclear deal approaches. Secretary of State John Kerry is expected to fly next week to meet with Iranian officials and other world powers to try and reach an agreement.

The Obama administration has said a nuclear deal not alter US policy regarding Iran’s other behavior. But officials have expressed hope a nuclear pact could lead to cooperation in the Middle East, particularly against ISIS, and ultimately moderate the Iranian regime.

The report also warned about the increase in so-called “lone wolf” attacks last year, citing attacks in Canada in October and Sydney, Australia, although it was difficult to assess whether attacks were directed or simply inspired by ISIS or al Qaeda and its affiliates.

“These attacks may presage a new era in which centralized leadership of a terrorist organization matters less, group identity is more fluid and violent extremist narratives focus on a wider range of alleged grievances and enemies with which lone actors may identify and seek to carry out self-directed attacks,” the report found.

The U.S. has working to “shift” it’s counterterrorism strategy to more effectively partner with countries where terrorist networks have a foothold, the report said. The US has assembled a sixty-plus nation global coalition to stop ISIS advances on the ground, counter its messaging and stem the flow of foreign fighters and financing.

The U.S. is also working with allies in North Africa and the Middle East to strengthen their counterterrorism capabilities and help them develop new laws to address the foreign fighter issue.

This year’s report marks the first that Cuba is not on the list of State Sponsors of Terrorism. Cuba was originally placed on the terror list in 1982 when the U.S. government accused the Fidel Castro regime of sponsoring communist groups in Latin American and Africa. The White House took Cuba off the list last month, after President Obama’s historic opening to Cuba in December.

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