Al Qaeda-aligned militants operating in Syria could already have access to "biological pathogens or weaponized agents," according to terrorism and biological warfare experts studying the region.

The possible acquisition by al Qaeda of these highly dangerous toxins has prompted bio-warfare experts to label the threat a "clear and present danger."

Extremist militants and other fighters tied to the terror group al Qaeda have continued to gain a foothold in key sections of Syria as the country’s civil war rages on.

Lawlessness has taken hold in many areas that are home to Syria’s biological weapons research hubs and mounting evidence indicates that al Qaeda fighters have capitalized on this security gap by looting the facilities.

"The Syrian civil war has left sections of the bio-pharmaceutical infrastructure destroyed and looting of labs has been observed, which could indicate that Assad is losing command and control over one of the most dangerous classes of weapons remaining in his weapons of mass destruction (WMD) arsenal," bio warfare and terrorism experts Jill Bellamy van Aalst and Olivier Guitta conclude in a new report.

Syrian President Bashar al-Assad is believed to have ample biological weapons stores in addition to the chemical weapons currently being confiscated by Western nations. These caches likely include various neurotoxins and deadly viruses, according to U.S. intelligence estimates and other experts.

"A very credible source has confirmed he saw, near Aleppo, a looted pharmaceutical laboratory, which was probably a cover for a biological weapons production site," Guitta and van Aalst revealed in a research brief published by the Henry Jackson Society.

The most recent looting took place in the embattled city of Aleppo, where the al Qaeda-backed group Al Nusrah is known to operate, according to the report.

"Syria's biological warfare programs are latent, highly compartmentalized, and dual use, run under both legitimate and clandestine programs, laboratories, institutes, and facilities," the report states. "The fact that this looting took place in the Aleppo area where the rebellion—and in particular Al Nusrah—is very strong tends to confirm that AQ may potentially be in possession of biological agents."

Guitta and van Aalst go on to warn that Assad’s supply of biological weapons are just as dangerous as his chemical arms, particularly if they fall into the hands of terrorist forces.

Recent reports from Syria suggest that al Qaeda’s top leaders have taken an interest in Assad’s bioweapons research facilities.

Al Qaeda’s primary biological weapon expert, Yazid Sufaat, was arrested in Malaysia. "His arrest is all the more concerning given that the [United Nations] has allowed the Assad regime to maintain its [bioweapons] program," according to the report.

Suffaat is a graduate of California State University, Sacramento, where he received a degree in biology, according to Guitta and van Aalst.

"In 1993, Sufaat established Green Laboratory Medicine, a pathology lab where he tried to weaponize anthrax on behalf of al Qaeda," according to the report. "Sufaat had direct ties to Nawaf Alhazmi and Khalid Almihdhar, both of whom were on Flight AA 77, which crashed into the Pentagon on 9/11."

Syria’s biological weapons are particularly vulnerable due to the dispersed and highly clandestine nature of the research program, according to the report.

"The structure of Syria's biological warfare programs are latent, compartmentalized, and spread across its remaining bio-pharmaceutical infrastructure," the experts write. "The programs are designed to be highly agile to allow swift production if required."

Osama bin Laden was known to be very interested in obtaining and using chemical weapons.

"It is a religious duty to have them; how we will use them? It is our business," he was quoted as saying in 1998. The Pentagon later revealed in 2004 that al Qaeda has a relatively sophisticated bioweapons research effort underway, the report notes.

Sen. John Cornyn (R., Texas) warned last month that Syria’s unsecured bioweapons pose a great threat to the region.

U.S. intelligence agencies have reported that Assad possesses various biological weapons and has an active research program underway.

"Based on the duration of Syria’s longstanding biological warfare (BW) program, we judge that some elements of the program may have advanced beyond the research and development stage and may be capable of limited agent production," Director of National Intelligence James Clapper wrote in an unclassified April report.

"Syria is not known to have successfully weaponized biological agents in an effective delivery system, but it possesses conventional and chemical weapon systems that could be modified for biological agent delivery," Clapper concluded.

Biological weapons could more easily be obtained and used by terrorist forces, experts warned.

"The problem with bio-weapons, unlike chemical or nuclear, is the quality and weaponization for dispersal that counts, not the quantity, Guitta and van Aarst wrote. "You do not need a stockpile and you do not need sophisticated delivery methods, in fact, that is no longer optimal. Bio-weapons are silent, and determining that an attack has occurred can be challenging."

UPDATE: A previous version of this article quoted a report from the Henry Jackson Society that said Sufaat was arrested in February 2013 while trying to enter Syria. The report's claim was inaccurate and has been updated.