DOD spokesman Capt. John Kirby could not confirm the exact number of al Qaeda fighters that had crossed the border into Syria during a briefing at the Pentagon on Thursday.
That said, he was adamant that there was no evidence that members of al Qaeda in Iraq (AQI) were operating with or worked their way into the opposition forces battling to depose Syrian president Bashar Assad.
The threat of Syrian rebel forces being co-opted by terror groups like al Qaeda has been the main crux of the Pentagon's argument against providing arms and military support for to the rebellion.
Gen. James Mattis, head of Central Command, among others have expressed concern that if heavy weapons are funneled into Syria, it’s possible those arms could later be turned against American or allied troops by al Qaeda fighters.
In testimony before the Senate Armed Services Committee in March, Mattis said that there is already evidence that al Qaeda operatives have infiltrated the rebel’s ranks and could have access to weapons supplied by the United States or its allies.
Regardless of whether members of al Qaeda's Iraqi affiliate are hooked into the Syrian uprising, the fact they have made their presence known in Damascus has led to their violent resurgence in Baghdad.
Al Qaeda's Iraqi cell has recently launched a string of brazen daytime raids against military and police outposts across the country. AQI members have also claimed responsibility for a number of deadly car bombings that have left hundreds of Iraqis wounded or dead.
The Army's top uniformed commander in March told lawmakers that AQI's recent aggressiveness can be linked in part to the growing unrest in Syria.
Army Chief of Staff Gen. Ray Odierno did not directly address the threat of insurgent cells crossing from Syria into Iraq in his testimony before the Senate defense panel, but he did admit that instability in Syria was adding to “concern” in military circles.
The ongoing rebellion in Syria was “adding a difficult piece” to efforts to maintain peace in Iraq, amid the recent surge in al Qaeda-directed violence.