Following their attempt to form a caliphate in the vast area of the Middle East under their control, ISIS leaders are said to be introducing passports to give the unrecognised state an air of legitimacy.
However experts believe the sinister black and white colouring of the document , which is based on the black jihadist flag flown by ISIS terrorists and warns of a 'deployment of armies' if the holder comes to harm while travelling abroad, proved the passports are little more than a symbolic gesture.
While ISIS has expressed a desire to expand its territory to include stretches of Europe, including Rome and Madrid, and have also threatened to raise the jihadist flag over Downing Street and the White House, the issuing of passports is more about sending a message than transporting fighters.
Issuing state documents is both a clear indication that ISIS considers its declared caliphate to be the world's newest state, and also to shrug off the threat posed to its existence by U.S. air strikes.
So far at least two versions of the alleged passport have emerged online - one bound in black leather with embossed lettering, and the other a simpler paper version laminated in shiny plastic.
Although it is not possible to prove the authenticity of either version, the latter has been widely shared on social media by respected terror experts and academics.
Dr Magnus Ranstorp, a Swedish academic who regularly briefs senior government and security officials on the threat of Islamic terrorism, tweeted a photograph of the plastic passport along with the caption: 'Illusions of a Caliphate. ISIS issue passports as part of psychological warfare.'
The image was also shared by Ghaffar Hussain, managing director of the world’s first counter-extremism think tank Quilliam, who joked: 'ISIS now issuing passports, I'm sure they won't create panic and alarm at airport check in desks.'
An image of the alternative leather-bound purported passport first emerged last month, as reported by Saudi-owned pan-Arab media service Al Arabiya.
An article published online claimed that document was going to be issued to 11,000 people living within territory controlled by ISIS militants, having been produced in a former goverment 'Identification and Passport Center' in the Iraqi city of Mosul.
As well as the inscription 'State of the Islamic Caliphate' at the top of the passport, the document also allegedly says: 'If the holder of the passport is harmed we will deploy armies for his service.'
The news comes as it emerged British forces have dropped a second round of aid to thousands of people trapped on a mountain as they flee advancing militants in Iraq.
The RAF was able to deliver 'essential supplies' over Mount Sinjar last night to assist the Yazidis, the Department for International Development confirmed.
The move follows an aborted attempt to deliver aid to the location in northern Iraq , which was called off when the RAF crew decided that the supplies could have injured the desperate people below. A first successful aid drop took place last weekend.
Downing Street has also confirmed that the RAF will send 'a small number' of Tornado jets to the region so they can be used, if required, to improve the UK's surveillance capability in the region to help the humanitarian effort.
The UK will also look at how it can play a role in getting equipment to Kurdish forces as they are better able to counter ISIS, Number 10 added.
Foreign Secretary Philip Hammond, who chaired a meeting of the Government's emergency Cobra committee to discuss the crisis yesterday, said the situation was 'challenging' and warned of a 'potential humanitarian disaster on a huge scale'.
DfID said the UK's second aid drop included 3,180 reusable water purification containers filled with 15,900 litres of clean water and 816 solar lamps that can also be used to charge mobile phones.
Barack Obama said the U.S.  had 'stepped up' its support to Iraqi and Kurdish forces engaged in the fight on the ground and was continuing with its daily humanitarian efforts.
Obama's comments comes as Iraq's incumbent Prime Minister Nouri al-Maliki appeared more isolated as he pressed his battle to remain in power.
Iraqi politicians and the international community have rallied behind a Shiite premier-designate who could be a more unifying figure, badly needed if the nation is to confront a spreading Sunni insurgency.
The power struggle in Baghdad comes as Iraq is battling militants from the al-Qaida breakaway Islamic State group in the north and the west. The fighting has become the country's worst crisis since the U.S. troop withdrawal in 2011.
Haider al-abadi, the deputy speaker of parliament  from al-Maliki's Shiite Dawa party, was selected by President Fouad Massoum to be the new prime minister and was given 30 days to present a new government to lawmakers for approval.
President Barack Obama called al-Ibadi's nomination a 'promising step forward' and urged 'all Iraqi political leaders to work peacefully through the political process.'
But al-Maliki, who has been in power for eight years, defiantly rejected al-Ibadi's nomination, insisting it 'runs against the constitutional procedures' and accusing the United States of siding with political forces 'who have violated the constitution.
By John Hall