This story was written by CBS News producer Robert Hendin for cbsnews.com.
The 2004 Madrid train bombings that killed 191 people cost a mere $70,000 and were financed primarily through the sale of hashish and ecstasy in Spain.
US officials say increasingly the sale of illegal drugs is the financing of choice for terrorists.
"Nothing generates money like drugs...it is the most lucrative illicit commodity that's trafficked," Michael Braun, the Chief of Operations for the US Drug Enforcement Administration (DEA) told a panel in Washington.
In fact, of the 43 groups identified as known terrorist organizations by the US State Department, 19 are linked to the drug trade.
While the men who carried out the Madrid plot had connections to Al Qaeda, they did most of the fundraising on their own. Al Qaeda central, as the Osama Bin Laden group is known, has a history of relying on drug money for support, primarily because of protection granted by the Taliban in Afghanistan. Now US authorities say they are seeing a more direct connection between drug money and funding for Al Qaeda terror activities.
Braun pointed out that more than 40% of the Taliban's money comes from the illicit trade of opium made from the widespread growth of poppy plants in Afghanistan, where the Taliban is based. But beyond the Taliban, "we are seeing more and more of an unequivocal connection with respect to Al Qaeda being involved in drug trafficking activities," he said. He told reporters the DEA has many open investigations into the connection, but would not provide further details.
While terror operations themselves are cheap, the maintenance of a terror organization on the whole is quite expensive. Recruiting, training, arms, fake documents, safe houses, and movement can cost hundreds of millions of dollars, and that's why many groups, including the leftist Colombian terror group, the FARC, and Mideast terror groups such as Hamas and Hezbollah have turned to drug trafficking to finance operations.
A recent UN report, shows that $322 billion was made last year by the global drug trade. $65 billion of that was from American drug users.
With so much of the world's cocaine coming from South America and Colombia in particular, the FARC is very involved in every aspect of the cocaine trade around the globe, and according to Braun the organization has become "the single largest cocaine trafficker in the world."
The FARC makes money by taxing the drug cartels, drug smugglers and drug farmers. Braun says the Taliban has picked up on the FARC's techniques and is now following the same model.
Braun called groups like the FARC, the Taliban, Hamas and Hezbollah: "hybrids -- They are one part terrorist organization and are becoming one part global drug trafficking cartel."
To combat the growing nexus between the international drug trade and terrorism, the DEA says it relies heavily on human sources on the ground in many different countries and has more federal agents stationed overseas than any other US law enforcement agency.
"This the face of 21st century organized crime," Braun stated. "But they are meaner and uglier than anything we've seen before."
By: Rob Hendin