The commander of al-Qaeda's Syrian affiliate has threatened to retaliate against US-led airstrikes on Islamist extremists by attacking the West, in a sign that the raids may have boosted support for the group they are intended to destroy.
Jabhat al-Nusra head Abu Mohammed al-Julani said that aerial bombardment would not defeat jihadi militants in Syria and that America and Europe would be targeted for reprisals unless citizens decried the attacks.
"Muslims will not watch while their sons are bombed. Your leaders will not be the only ones who would pay the price of the war," Julani said in a message posted on jihadi internet forums, Reuters reported. "You will pay the heaviest price."
A US-led coalition designed to "degrade and destroy" the extremist militant Islamic State (IS) launched a series of strikes on the group in Syria on September 23. However, it has also struck other hardline Islamist factions, and killed at least 50 al-Nusra fighters last week, according to the UK-based Syrian Observatory for Human Rights.
Washington has been conducting airstrikes on IS targets in Iraq since August, when the militants made a push into territory controlled by the Western-backed Kurdish Regional Government (KRG) and seemingly threatened the capital of Erbil. American officials subsequently cobbled together a broad anti-IS coalition made up of both European and Arab states earlier this month. A number of European countries, including the UK, France, Holland and Denmark have launched, or agreed to launch strikes on IS targets in Iraq, but so far only the US, Bahrain, Jordan, Saudi Arabia, the United Arab Emirates and Qatar are known to have hit the group in Syria.
IS and al-Nusra have similar ideologies and both wish to establish sharia law in Syria. However, the two have not enjoyed a good relationship. When IS appeared in the country in April 2014, it attempted to merge with al-Nusra but was spurned by both Julani and al-Qaeda head Ayman Mohammed Rabie al-Zawahiri.
Since then, the two groups have stuck to very different operating models. The predominantly Syrian al-Nusra has worked closely with the opposition forces, such as the Islamic Front and Western-backed Free Syrian Army and proven to be a capable and formidable force against Syrian president Bashar al-Assad's troops. Many of its fighters are viewed locally as being more moderate than official ideology suggests and have focused primarily on overthrowing Assad's government.
IS, meanwhile, has concentrated on seizing territory, including a large swathe of northern Iraq in June, and implementing its brutal and extreme interpretation of Islamic law in areas under its control.
As a result, IS and al-Nusra have clashed in a series of increasingly bloody encounters, even carrying out suicide attacks against each other. An initially reluctant al-Nusra was part of an opposition group which launched a concerted attack against IS earlier this year, beating them back to the area surrounding their stronghold of Raqqa in north central Syria.
Al Qaeda completely disowned IS in February for being too extreme even for them, but Zawahiri has repeatedly, and ineffectively, pleaded for the groups to stop fighting.
What he could not accomplish, the airstrikes may have. Al-Nusra membership are now pressing for reconciliation with IS against Western "crusaders".
Other parts of Julani's message were clearly designed to gather support from other Syrian rebel factions not to take advantage of an airstrike-weakened IS, despite previous disagreements. "(Islamic State injustice) should not push any of you to be driven behind the West and take part in the alliance which they want to use to end jihad," he said, Reuters reported.
This goal may be helped by the US's strategy of only deploying strong language against Assad's regime, which is seen as a main foe even by rebel groups fiercely opposed to IS as it has killed tens of thousands of Syrians. US-trained and equipped Harakat Hazzm, for example, condemned attacks in Syria last week, saying that they might strengthen the government.
Follow John Beck on Twitter: @JM_Beck