Zhang Youjie / Xinhua Press / Corbis Syrian President Bashar al-Assad receives an interview with Russian newspaper Izvestia in Damascus, on Aug. 26, 2013.

It’s an uncomfortable truth for policymakers in Washington and other Western capitals considering a strike on the Syrian regime of President Bashar Assad: a military assault on regime targets in response to last week’s alleged chemical weapons attack could inadvertently provide an assist for al-Qaeda-linked groups that are fighting the Syrian government. As an attack from Western countries seems imminent, so too does some kind of military response from the Islamist extremists.

A Syrian affiliate of al-Qaeda has vowed to ignite a “volcano of revenge” against the Syrian regime, which it blames for the apparent chemical weapons attacks near Damascus. The statement was first reported and translated by the Jihadist threat monitoring network SITE Intelligence Group late Tuesday night.

According to SITE, the statement was issued on August 26 by a consortium of eight Syrian rebel factions, including a branch of the al-Qaeda-linked Islamic State in Iraq and Syria. The eight factions declared a military campaign against the “main joints” of the Syrian regime “including security branches, support and supply points, training centers, and infrastructure.” ISIS is a newly formed group, but the al-Nusra Front, which makes up the Syrian side of ISIS, is thought to be behind some of the most devastating suicide attacks against the regime to date, as well as significant battlefield victories over multiple military installations throughout the country.

By issuing such a threat, ISIS may be seeking to supersede American action in Syria, giving it a public relations edge in a region largely aligned against Assad yet uncomfortable with the idea of U.S. military intervention. A successful ISIS strike against the regime while the West deliberates appropriate action would read well on the Arab street and among other Syrian rebels. U.S. action in Syria, if it happens, will have far greater impact on the regime than anything ISIS can pull off but al-Qaeda may be racing to score key points in the region before a Western attack.