The Islamic State (ISIS) has found an enemy worse than the West—its fellow Muslims belonging to the Shia sect.

In the latest issue of its online magazine Dabiq, ISIS declared war on Shiites who it calls "the followers of deviant desires.''

Titled "The Rafidah: Front Ibn Saba' to the Dajjal," the main article in the magazine's 13th issue contains pages of violent rhetoric directed against Shiites.

"Rafida'' is derogatory term for Shiite Muslims and can be translated as "rejecters,'' according to Fox News.

The Sunni terror group devoted a majority of its 56 pages in its new issue justifying the killing of Shiites or Shia Muslims, who they say are apostates to the Sunni majority.

"Some of them are Jews who fake Islam to spread their deviance, just as Paul of the Jews faked Christianity to spread his deviance,'' the magazine says

"The Rafidah hate Islam just as the Jews hate Christianity. They did not enter Islam longing for Allah fearing Him, rather out of spite for the people of Islam and so as to inflict harm upon them,'' it states.

It also says: "Our condition dictates that we deal with the matter with courage and clarity and endeavour for a solution... The solution as we believe, and Allah knows best, is to expose the Rafidah...to fight them and stop them."

While this is not the first time ISIS has called for the killing of Shia Muslims, this time around the Sunni jihadist group is calling for a concerted effort to wipe out the Shiite population of the Middle East, according to Ryan Mauro, a national security analyst for the Clarion Project.

"At first glance, it may seem odd that ISIS is focusing its efforts against fellow Muslims and not the West. But this is all part of the elaborate campaign on the Islamic State's part," Mauro said.

He noted that attacking U.S. and Europe is still crucial for branding purposes since this will help them make their case look favourably in the eyes of Allah, and that they are growing stronger, regardless of whatever territorial losses they suffer on the ground.

''Even though the Americans are also a major enemy, [to ISIS] the Rafidah are more severely dangerous and more murderous than the Americans,'' the analyst said.

The propaganda magazine also praised the Dec. 2 terrorist attack launched in San Bernardino, California.

It said the couple who staged the attack demonstrated Muslims' willingness to make sacrifice for the sake of ''fulfilling their duty to Allah.''

An article on the recently killed executioner for ISIS, "Jihadi John," and a piece blasting Saudi Arabia were also included. It likewise praised the widows of ISIS fighters.