"Unless the money is actually in the US financial system, you have to point out to these governments where the money is going and try to work with them to make sure it goes to legitimate groups," said one US official who spoke with The Washington Times on the condition of anonymity because of the sensitivity of intelligence related to tracking such money.
"The US can't shut down bank accounts in Kuwait or Qatar," the official said. "We can tell them, 'Look at what this person is doing.'"
The approach has worked with variable success over the past decade, during which US authorities have worked closely with counterparts in such nations as Kuwait, Qatar and Saudi Arabia to choke off streams of cash to al-Qaeda's core leadership in Pakistan and Afghanistan.
But when it comes to stemming the flow of aid to Salafist and al Qaeda-linked groups inside Syria, the strategy has been less successful — suggesting authorities in the Persian Gulf states now may see American pressure for such action as less worthy than previous calls to block cash to al-Qaeda.
"In some nations where they have had success in clamping down on terrorist funding for al Qaeda's core, this is a source of funding that has not really been clamped down on," the official said.
The extent to which that money is aiding the rise of extremists in Syria seemed to burst open last month when 11 Syrian militant groups, including the Nusra Front — an organization US officials link to al-Qaeda — banded together in a public rejection of the more moderate opposition groups outside the country that are receiving aid from Washington.
By calling for a new government in Syria to be ruled by Sharia law, the newly formed coalition dealt a major blow to US-led efforts for a regime change in the country.
Although the Islamic State of Iraq and the Levant (ISIS) — another rebel group with al-Qaeda ties in Syria — was left out of the coalition, analysts say, it, too, is growing dangerously in the war zone. As the extremist foothold has deepened, so have reports of abuses and war crimes carried out by opposition militants.
A report released last week by Human Rights Watch said members of the Nusra Front and ISIS were among rebel fighters who killed some 190 unarmed civilians during an August offensive on villages perceived to be supporting the government. The report said 67 of the civilians were slain at close range while trying to flee.
The bottom line is that the landscape of extremist groups among the opposition has grown increasingly complex over the past year, said Mouaz Moustafa, executive director of the Syrian Emergency Task Force, an advocacy arm of Syria's more secular political opposition that lobbies in Washington for a greater US role in the conflict.
"The Islamic State of Iraq and the Levant has increasing power and influence in places like Aleppo and Raqqa Province," said Mustafa. "But at the same time, other Islamist battalions have coalesced and improved their organizational structures while rejecting both the ISIS and the more secular outside political coalition."
He said that "all of these groups are getting assistance" and that the task of pinning down the precise source of the money is difficult. "That's the million-dollar question," he said.
When it comes to ISIS, said Moustafa, "you're talking about al-Qaeda's network, and I would assume most of the aid and resources they're getting comes directly from Iraq, where the system was already in place to raise money going back to the rise of al-Qaeda in Iraq several years ago."
US officials say that system has relied heavily on the activities of an Iraq-based al-Qaeda "facilitator" named Muhsin al-Fadhli.
A little-reported press release circulated by the US Treasury Department last October described al-Fadhli as "a veteran al-Qaeda operative" who provided "financial and material support" to al-Qaeda in Iraq leader Abu Musab Zarqawi.
Zarqawi was known for orchestrating a series of gruesome bombings and beheadings in Iraq before US forces killed him in 2006. But the activities of al-Fadhli's network supposedly have carried forth — and have evolved toward tapping a reserve of Kuwait-based sympathizers to fund extremist groups fighting in Syria.
"In addition to providing funding for al-Qaeda activities in Afghanistan and Pakistan, this network is working to move fighters and money through Turkey to support al Qaeda-affiliated elements in Syria," according to the Treasury Department press release. "Al-Fadhli also is leveraging his extensive network of Kuwaiti jihadist donors to send money to Syria via Turkey."
That extremist elements of Syria's opposition are gaining strength appears to expose the limitations of the US government to block the flow of such money — or at least to persuade partners in Kuwait and other Persian Gulf nations to do so.
Officials at the Kuwaiti Embassy in Washington did not respond to a request by The Times to comment for this article.
But an article published last month by Foreign Policy shed some light on the situation. In the article, William McCants, a former senior adviser in the State Department's office of the coordinator for counterterrorism, wrote that "the (Persian) Gulf monarchies have not been able or willing to stem the tide of private money their citizens are sending to the Salafi charities and popular committees."
"Kuwait in particular has done little to stop it because it lacks an effective terror financing law and because it cannot afford politically to infuriate its already angry Salafi members of parliament," wrote Mr. McCants. "Qatar and Saudi Arabia have tried to crack down on fundraising for the Salafi militias but their citizens just send their money to Kuwait."
The rise of extremists among Syria's rebels, meanwhile, has set off a political storm in Turkey, where the leadership of the nation's main opposition party is accusing the government of Turkish Prime Minister Recep Tayyip Erdogan of supporting al Qaeda-linked groups in the nearby war zone.
Kemal Kilicdaroglu, who heads the Republican People's Party — or CHP, as it is known in Turkey — declared in a speech last month that al Qaeda "is now under the protective wings of Erdogan."
Analysts say such claims are based mainly on politics, but also partly on the ease with which jihadist foreign fighters seeking to join Syria's opposition rebels have been able to cross the long border between Turkey and its southern neighbor over the past two years.
The situation prompted concern among some national security and intelligence circles in Washington last month when a German news report was posted online that purported to show foreign fighters from around the world, bound for Syria, flowing through a jihadist safe house along the Turkish side of the border.
The report showed footage of a gray-bearded man who, according to the report, had arrived from California to join the war in Syria.
Asked about the German report, one senior US intelligence official told The Times that "it would be inaccurate to suggest the government of Turkey is helping foreign jihadists enter Syria."
"Preventing extremists from crossing the roughly 500-mile Turkish border to join the Syrian opposition is among the many security challenges Turkey faces," said the official, who spoke on the condition of not being named in this article.
A Turkish government source, who also asked not to be named, said the US comment was unsurprising "because American authorities are very well aware of our operations against al-Qaeda."
"To claim that Turkey is supporting terrorism is an insult to Turkey," said the Turkish source. "We're trying to control our borders as much as we can."
Others say the situation is complex and nuanced by Turkey's domestic and regional political strategies.
Paul Pillar, a former CIA officer who now teaches at Georgetown University, said that "if the Erdogan government is relaxed about aid getting into the hands of Nusra, it's because they see Nusra as one of the more effective fighters against Assad (administration) and not because this is some kind of backdoor way of aiding whatever particular ideology Nusra represents."
BA/BA