U.S. involvement is Syria is becoming more complicated. “We have broad-based concerns about the conflict in Syria, period,” said Pentagon chief spokesman George Little. The pipeline runs from the Persian Gulf states, and is currently used to provide humanitarian aid to Syrian rebels, but it's possible that it could help the opposition, as well. “We have concerns about weapons proliferation inside Syria and yes, we do have concerns that some of those weapons could fall into the wrong hands," said Little.
Wired explains the threat that the open pipeline creates:
That proliferation fear illustrates the dilemma that the Obama administration’s Syria policy has created for itself. The CIA helps keep the pipeline to the rebels open, while seeking to gather intelligence on the Syrian opposition itself. But the official line is that the U.S. isn’t providing any rifles, rockets, mortars, missiles or spy tools to the rebels directly, partially out of concern that the U.S. doesn’t sufficiently know whom it’s arming. Critics, like Sen. John McCain, argue that President Obama is “AWOL” on Syria, allowing Iran-backed dictator Bashar Assad to slaughter civilians, and call for greater U.S. support for the rebels. But that could lead to a situation where the U.S. inadvertently arms its regional adversaries, as it did in Afghanistan in the 1980s, or unleashes weapons whose ultimate destination spreads far beyond the battlefield, as occurred in Libya during last year’s war.
However, Little said, “I’m not going to speculate on prospective changes in policy." For now, the pipeline remains open.