An advanced surface-to-air missile thought to have been supplied to Syrian rebels by Qatar against American wishes has been filmed in the hands of Isil jihadists.
A militant was shown firing a Chinese-made FN6 shoulder-mounted missile, with a later image suggesting it had brought down an Iraqi army helicopter. The attack was said to have happened during the battle for Baiji, a town that houses Iraq's biggest oil refinery.
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The FN6, a modern weapon that is still being made, is more powerful than the older, Russian-made missiles previously seen in the hands of rebels and the Islamic State of Iraq and the Levant (Isil).
The helicopter the militants claimed to have brought down, an Mi-35M, was of a type provided to Iraq by Russia in the past year and is meant to be fitted with defence systems.
The new missile raises the threat to US Apache helicopters, which have been returned to Iraq as part of the US-led coalition support for the Iraqi army.
"The US Apaches deployed to Baghdad will have countermeasures, but I cannot comment on whether they would be more effective than the ones on Iraq's new Mi-35Ms," said Jeremy Binnie, of IHS Jane's, who spotted the Isil video.
The US has argued against giving Syrian rebels surface-to-air missiles despite the Assad regime's bombardments of civilians, for fear they would end up in the hands of jihadists. Last year The New York Times reported that Qatar, which has been criticised for its support of more extreme rebel factions, sent in a batch.
The Iraqi government maintains there is no threat to civilian aviation.