© Mail OnlineThe serial numbers on the aircraft pictured correspond to numbers on known Iranian fighter jets
Military expert Joseph Dempsey believes the latest set of aircraft to be delivered to Iraq is Iranian, despite steps being taken to mask its origin.
The U.S. has just announced it's sending an additional 300 troops to Iraq, raising its total presence in the war-ravaged country to 750.
Those troops will now be working alongside the newly delivered Iranian fighter jets to form an unlikely international military aid package.
Joseph Dempsey, an analyst for the IISS's Military Balance Online publication, said new footage showed Iraq's latest Su-25 Frogfoot attack aircraft originated from Iran.
Their arrival follows a delivery of identical aircraft from Russia - but with a number of key distinctions.
He said video footage of the fleet showed serial numbers matching those from known Iranian aircraft, while their camouflage scheme was unique and attempts to conceal Iranian insignia were noticeable.
'Although these aircraft were likely delivered to Iraq by Iranian pilots, it is unclear who will now be responsible for crewing and maintaining them.
'Given this recent apparent growth in their Su-25 inventory, it seems increasingly unlikely that Iraq retains the capacity to operate this type of aircraft in any significant number without some level of external support.
'Whilst the presence of Iran-sourced aircraft in Iraq is clearly significant, the exact circumstances surrounding their presence and intended use remain unknown, as does the existence of any wider arrangement between the governments of these neighboring countries to counter the ISIS threat.'
Iraq has been vocal in its opposition to ISIS, with public protests held in the capital last week and new reports of drone strikes taking place across its border.
Protests took place in Tehran, Iran, last week where the public voiced its concerns about ISIS - it is believed Iran has now supplied fighter jets to assist the Iraqi Government to repel the Islamic extremists
Only days ago did ISIS formally announced the creation of its caliphate, or Islamic State, across the territory it holds in Syria and Iraq.
Its push across Iraq in recent weeks has been brutal, with more than 2,400 people killed in the month of June alone.
The group is responsible for committing a number of mass executions and bloody atrocities during its surge to the edge of the city of Baghdad and has called on all Muslims to join its campaign.
Yesterday, the leader of the extremist group called on Muslims to come to the territory his group has seized to help build an Islamic state, declaring: 'The earth is Allah's.'
Abu Bakr al-Baghdadi said: 'In this virtuous month or in any other month, there is no deed better than jihad in the path of Allah, so take advantage of this opportunity and walk the path of you righteous predecessors.
'So to arms, to arms, soldiers of the Islamic, fight, fight.'
ISIS is taking the route pioneered by Erwin Rommel.
If you don't have enough ammo, seize the enemy supply dumps.
The ammo won't work in your stuff? Piece of cake.
When the Iraqi Army flees the battlefield, seize and repatriate thier arms, using them to arm your existing ranks. They do NOT destroy the booty, they use it.
Need more gas & diesel? No problem, just seize a refinery or two and fill 'er up.
That is how the Desert Fox did it, and this is how ISIS is doing it.
Talking heads who say that ISIS is overreaching are full of hot air.
They are currently only effectively opposed in the vincinity of Baghdad, with the US and Iran as strange bedfellows.
What do you want to bet that Iran took an opportunity to offload thier dated aircraft to get $$$ to buy more advanced models from Russia?