The propaganda organs of the Islamic State have called for biological attacks on the West, with one poster depicting San Francisco.

'We will make you fear the air you breath (sic),' reads the text above the San Francisco skyline, with a hooded figure in the foreground holding a device spewing green gas, in an image obtained by the Middle East Media Research Institute.

It follows the recent release of a video calling for lone wolf biological attacks, offering crude instructions to followers on how to concoct 'the most serious plague' from 'the feces and droppings of rats'.

An ISIS propaganda poster depicts the San Francisco skyline and promises biological attacks

'We invite you, oh Muwahid [monotheist] who lives between the Mushrikeen [idolaters] that you clean the dust of humiliation and to renew the fatal nightmare in the land of the devil worshipers with a silent destructive weapon,' the video urged, according to a transcript published by MEMRI.

Though biological warfare is typically associated with advanced and hard-to-obtain agents such as anthrax, the video offered more rudimentary options for aspiring ISIS fanatics.

The video advised that Hantavirus is sometimes found in rat droppings, and also suggested combing through human excrement to obtain Cholera and Typhoid bacteria.

'This is the expected punishment for the oppressive US policy,' the video's narrator says.

Fighters of the Syrian Democratic Forces walk down a street in Raqa past destroyed vehicles and heavily damaged buildings in October, after expelling ISIS from the city

A 2016 West Point study found that while ISIS has long advertised its desire to obtain and use sophisticated biological weapons, the group faced 'significant practical challenges' in the endeavor, including the lack of sophisticated personnel and technology, and sufficiently reliable power grid in the territory it controlled.

'Biological weapons are very unlikely to be developed by the Islamic State as a mass casualty tool,' the report said.

'Western medical countermeasures and response capabilities were able to handle the 2001 anthrax attack and quickly contain Ebola in the United States in 2014. All this suggests the impact of a deliberate biological attack by the Islamic State in the West would be extremely limited.'

Since then, ISIS has lost significant ground in Syria, but they retain a presence in the east of the country and in the vast Badiya desert that sweeps through its south.

The Syrian government has been fighting in recent weeks to expel ISIS fighters from a patch in the neighboring province of Daraa.