Russia has started sending military helicopters and fighter jets to Iraq, according to Interfax news agency.
The report comes after Iraq's defence minister visited Moscow to press for extra arms to help combat a growing insurgency at home.
"A number of contracts with Iraq have entered into force and are being fulfilled," said a Russian defence exporter, as quoted by Interfax.
Moscow has already begun deliveries of Mi-35 helicopter gunships and Su-25 fighters that can provide support to ground troops, the source added.
Iraq has also signed contracts for Mi-28 attack helicopters and mobile Pantsir-S1 surface-to-air and anti-aircraft artillery systems.
In the wake of the Malaysia Airlines plane crash over eastern Ukraine, Russia believed that deteriorating relations between Washington and Moscow could lead the US to attempt to freeze Iraq's weapons purchases from Russia, the source added.
Iraqi officials said Defence Minister Saadun al-Dulaimi had left for Moscow to boost military cooperation.
"Dulaimi will meet the Russian defence minister and other officials to urge them to provide Iraq with weapons, equipment and modern military aircraft," Staff Lieutenant General Mohammed al-Askari told AFP.
Iraq signed contracts worth around $4.3bn in 2012 in order to supply 36 Mi-28 attack helicopters and 28 Pantsir units, according to RosTec.
Iraq's embattled Prime Minister Nouri al-Maliki also ordered second-hand fighter jets from Russia in June, as the Islamic State captured vast swathes of territory in northern Iraq after central government security forces fled.
At the time, Maliki blamed the rapid success of the insurgency on the army's lack of airpower, as Islamic State fighters formed coalitions with Sunni militants to sweep through key cities including Mosul and Tikrit on the road to Baghdad.
The conflict has since stabilised with the Islamic State still entrenched in Mosul.